Peru has twenty-eight out of the thirty-two defined climates in the world, and of the 104 classified zones of life, eighty-four are found within its borders. The southeast further encapsulates this variety, from brittle ice to sweltering jungle. With nearly all the major Inca ruins (including Machu Picchu), Lake Titicaca, the most pristine rainforest in the Americas, the source of the Amazon, and the highest biological diversity on the planet, it can safely be said that this area is unparalleled on earth.

The Andes divide the driest place on earth from one of the wettest. The Atacama Desert, on the coastal plains, is the driest hot desert in the Americas, and has areas where rain has never been recorded. Yet the cloud forest on the eastern slopes receives an average 20 feet (6 m) annual rainfall —six times greater than soggy Britain. These mountains are life-giving, but global warming is diminishing their power. The river Amazon begins here in pools of melted ice, but the accelerating rate at which the glaciers retreat is alarming.

The Snow Peaks were the most powerful earthly deities in Inca times and the four ranges of Vilcanota, Vilcabamba, Carabaya and Urubamba are venerated to this day. Prayers to Christ and the Virgin often include the name of the nearest Apu (mountain god), and offerings are made to them from the highest altiplano to the depths of the forests.

Not far off the coast from the scorching desert lies some of the best fishing in the entire Pacific Ocean. It was fishermen in this region who first noticed the El Niño, a significant warming of coastal waters around Christmastime, summer in the southern hemisphere. Normally, the cold waters of the Pacific here maintain the rain shadow that keeps the Atacama so dry. El Niño wrecks havoc upon coast, bringing torrential downpours on desert which then blooms; wildflower seeds preserved by the arid conditions spring to life with the rains. Native wisdom has held for millennia that it rains every twenty years in the desert; it is hard to ignore the climate's increasingly unpredictable behavior in the past few decades.

Even without El Niño, some regions of the arid coast experience coastal fogs or mist, and even drizzle during the summer. Lima is shrouded in a grey smoggy mist called the garúa between May and November.

In the mountains and the jungle, the climate is more accurately divided into the wet season (October through April) and the dry season (May through September). While there can be rain during the dry season, it can be unrelenting during the wet season, with heavy rains causing problems like washed out roads. Heavy clouds can completely obscure the gorgeous views of the mountains and valleys.

The Tahuantinsuyu, the Land of the Four Quarters, as the Inca empire was known before the Conquest in 1533, stretched along the Pacific from about the second degree north to the thirty-seventh degree of south latitude; a line which also describes the western boundaries of the modern republics of Ecuador, Peru, Bolivia, and Chile.

When the Inca, God-King, reigned supreme, there was order in everything. Spectacular feats of engineering and irrigation triumphed over one of the most barren environments on earth, supporting the cultivation of an area farmed today. The real strength of the Inca state lay in efficient administration; it made an art form of harnessing manpower within a strong hierarchical social system. Taxes in the form of state labor and tributes kept the network of paved roads and agricultural terraces perfectly maintained, while the storehouses were filled with sufficient cloth, weapons and food to sustain the entire population through times of war or famine. Movement throughout the empire was strictly controlled and regional costumes were encouraged in order to develop identity. Private property was an unknown concept for which there were no Quechua words. Every citizen was a part of the ordered whole, their lives interlocked by duty like the fluid masonry of their walls. Ama suwa, ama qella, ama lulla —"Don't lie, don't steal, don't be lazy" —was a common greeting; "Nor you," the reply.

It is almost inconceivable, then, that an army of 169 men could conquer the largest empire in the Americas, but the timing of the Spanish incursion coincided with a series of catastrophes that left Tahuantinsuyu vulnerable. A mysterious epidemic, possibly European smallpox introduced during the invasion of Mexico, had killed tens of thousands, including the Inca Huayna Qapaq, his heir Ninan Cuyuchi, and much of the Inca court. The ensuing civil war waged between his sons Huascar and Atahualpa lasted several years. Then, at the moment of Atahualpa's triumph, the strange bearded white men arrived.

The speed of Tahuantinsuyu's expansion was its weakness. Many of the northern civilizations still saw the Inca as hostile invaders, so the Spanish were able to raise auxiliaries from battle-hardened tribes such as the Canari and Chachapoya. In the sixteenth century, Spanish soldiers were some of the finest in the world, their weapons and strategies honed on campaigns against the Moors and Aztecs.

In November 1532, Francisco Pizarro made a reckless decision: he would leave the coast of Peru and march inland to meet the Inca Atahualpa. The Conquistadors were frightened by the ravines and passes in which they could easily have been trapped, and their horses had difficulty climbing the steep trails. A year later, after the tiny band of invaders had seized Atahualpa, melted down his huge ransom of gold and silver, broken their promise to release him, and then executed the Inca, they were free to march south to the imperial capital, Cusco.

A sixteenth-century Spaniard, Miguel Agia, summed up the contrast between the conquerors and their subjects: The Spaniards and Indian are diametrically opposed. The Indian is by nature without greed and the Spaniard is extremely greedy, the Indian phlegmatic and the Spaniard excitable, the Indian humble and the Spaniard arrogant, the Indian deliberate in all he does and the Spaniard quick in all he wants, the one liking to order and the other hating to serve.

The excesses of the European masters have been multiplied in modern Peru, but the indigenous character has not changed greatly. Indians remain conservative, stoic, uninterested in politics but loyal to family and community, and highly spiritual.

Peru's population of about 23 million is divided almost equally between the highlands and the population centres of the coast, and the division marks a sharp cultural as well as geographic divide. The inland regions are marked by extreme poverty and subsistence agriculture, while the fertile river valleys of the lowlands have produced a wealthier, more cosmopolitan culture. Almost half of Peru's people are Indian, while another one third or so are mestizo. About ten percent are of European descent, and there are significant African and Asian minorities. Although Spanish is Peru's official language, a multitude of indigenous languages continue to hold sway in the highlands.

Known as Vilcamayo to the Incas, and El Valle Sagrado de los Incas to the Spanish, the Sacred Valley is the portion of the Urubamba river valley from Pisac to Ollantaytambo. The Sacred Valley was home to several cultures prior to the rise of the Inca Empire. These pre-Inca cultures include the Chanapata (800-300 BC), the Qotacalla (500-900 AD), and the Killke (900-1420 AD). The Inca controlled the valley for little over a century.

The Río Urubamba, a section of which is called the Vilcanota, was a central element of the Inca's cosmology. They viewed as the earthbound counterpart of the Milky Way. The river feeds this fertile valley, and the majority its inhabitants live a life little changed since the arrival of the Spanish. Farming is done largely with the help of wooden plows pulled by oxen, travel is largely by foot, and the native population speaks Quechua. The salt pans of Salineras de Maras are still in use.

The valley is guarded at either end by Inca citidels hanging high above the valley floor. The stronghold at Ollantaytambo was the only Inca fortress to withstand a sustained Spanish attack. After the unsuccessful seige of Cusco in 1536-37, Manco Inca withdrew to Ollantaytambo. Hernando Pizarro followed, with a force seventy horsemen, thirty foot soldiers, and a large native force. They arrived at Ollantaytambo to discover the Incas had diverted Rio Patacancha to make valley impassable. Meanwhile, Manco Inca had joined forces with neighboring jungle tribes to form a force that reportedly overflowed the valley's sides. The Spanish eventually retreated under cover of darkness, abandoning much of their equipment. Then reinforcements arrived from Spain, and Manco Inca retreated further down the valley to Vitcos and Vilcabamba.

Today, the Sacred Valley is a quiet place, but it is slowly changing as its attraction as a tourist destination grows. Many tourists are preferring to center their exploration not in Cusco, but in the Sacred Valley itself, taking several day trips and returning to one of the excellent hotels that have begun to spring up in Urubamba, Yucay, and Ollantaytambo.

Cusco was the capital city of the Incas. In fact, the name itself means "navel;" Cusco was considered the center of the world by the Incas. The four quarters of Tahuantinsuyu were centered on the lofty city, perched at 11,000 ft. (3600 m) elevation.

Before the Inca settled in the region, other cultures settled the area, including the Killki culture (700-800 AD) and the Lucre culture (around 1000 AD). Inca legend credits Manco Capac and his sister Mama Occlo with the founding of Cusco, around 1200 AD. It wasn't until Pachacuti assumed power in 1438 that the Incas became true empire-builders.

The only Inca ruler to not live in Cusco was Atahualpa, who was on his way to Cusco when captured by Pizarro in Cajamarca. Pizarro reached Cusco on November 15, 1533. Cusco fed on their dreams of El Dorado, as they saw Koricancha, the Temple of the Sun, with its walls covered in sheets of gold.

Pizarro officially founded the Spanish city of Cusco on March 23, 1534, dividing it among eighty-eight of his men who remained as settlers, with Manco Inca set up as a puppet ruler with a new palace just below Sacsahuaman. The battles among the settlers for dominance, and the associated abuse heaped upon the native residences, provoked Manco to rebel. Leading a force of one hundred thousand, he trapped two hundred Spanish forces in Huacapata, located roughly in the same spot at the modern Plaza de Armas. Incredibly, the desperate Spanish counterattack on the temple-fortress of Sacsahuaman succeeded, marking a critical turning point in history, for the Inca could have regained control of all of Peru except Lima had they won at Cusco. Manco and his succeeding son, Tupac Amaru, held out at Vilcabamba until 1572. Cusco has lived in relative peace since, except for the great earthquake of 1650.

Cusco today is a vibrant city of some three hundred thousand, the vast majority of whom are native Quechua Indians. Despite being a major tourist destination, both for its own treasures and as a staging point for the Sacred Valley and Machu Picchu, Cusco has managed to hold on to its own distinct flavor. It retains a natural charm that is irresistible.

For many tourists, Machu Picchu is the highlight of their trip to Peru. Visiting Machu Picchu will exceed the wildest of expectations, inspiring awe and the deepest respect for the skill of the Incas as builders. Many are surprised to learn it sits at an elevation of only 8,040 ft. (2450 m), 2,600 ft. (1150 m) lower than Cusco. It perches 1,500 ft (450 m) above the Río Urubamba on a narrow ridge between the mountains Machu Picchu and Huayna Picchu.

The site was discovered in 1911 by Hiram Bingham, who was looking for Vilcabamba, the last hiding place of Manco Inca. There is still some debate over the true nature of Machu Picchu, but majority opinion holds it is a royal retreat and sacred center begun by Pachacuti in the mid 1400s and occupied until shortly after the arrival of the Spanish.

Machu Picchu is filled with astonishingly beautiful structures that blend harmoniously with the surroundings. From every perspective, the buildings and stones mimic the shapes of the surrounding mountain peaks. The carved stone Bingham dubbed the Intiwatana, the Hitching Post of the Sun, abstractly echoes the shape of Huayna Picchu. Archaeologists argue this stone does not play the same role as other intiwatana stones at sites like Pisac, but do agree it held special significance as an element of mountain worship. They also agree it is not a sundial.

One of the most beautiful structures at Machu Picchu is the Temple of the Sun, a solar observatory that features the finest stonework of the site. Bingham called its north wall "the most beautiful wall in America." It is built on a natural rock structure, partially encircling the top of the structure. Here the rock has been deliberately cut to form a ledge that bisects the sunlight passing through the eastern window at sunrise on the winter solstice. Underneath, the rock structure forms a cave, misleadingly named the Royal Tomb by Bingham. No burial has been found in the cave. Archaeologists now think the cave represents the sacred heart of the mountain.

Machu Picchu is a photographer's delight. The combination of sun, stones, mountains, and buildings result in shadow dance that lasts all day.

Lima is perhaps unfairly judged against the astonishing offerings of places like Cusco and Machu Picchu. It's frequently ignored on tourist itineraries. But as the home of over eight million people, about a third of Peru's population, Lima is a lively, bustling city with plenty to offer.

Lima was founded in 1535 by Francisco Pizarro, and became the capital for the viceroyalty of Peru, which included modern day Peru, Bolivia, Ecuador and Chile. The "City of Kings" was the richest and most powerful city in South America until the early nineteenth century. In 1551, the University of San Marcos, the oldest on the continent, was founded in Lima. The Inquisition was headquartered in Lima from 1570 until 1813.

Lima was devastated by a tremendous earthquake in 1746, leaving five thousand people dead, and leveling most of the city's buildings. It was rebuilt with an eye to the European architecture of the day. While Lima prospered as a port during the nineteenth century, it was during the middle of the twentieth century that Lima exploded, growing from 300,000 inhabitants in 1930 to 3.5 million in the 1970s. Unable to absorb the influx of immigrants from the provinces, this period saw the eruption of pueblos jóvenes (young towns) on the outskirts of Lima.

While Lima is still recovering from this explosive growth, it has much to offer, as the modern center of Peruvian life. For the tourist, it houses some of the best museums in the country, including the Museo Arqueológico, the Museo de la Nación, and the Museo de Oro. Lima Centro offers colonial-style churches and buildings. Excellent shopping can be found in Miraflores, and Barranco is the area to visit for Lima's exciting nightlife.

Realm of the Incas is a celebration of the extraordinary diversity at the heart of Tihuantinsuyo, or 'Land of the Four Quarters,' as the Inca Empire was known before its conquest in 1533. Max Milligan's book charts a journey of breathtaking beauty, from the sacred snows of the Andes down into the virgin Amazon rainforest, encompassing the most richly biodiverse area on the planet.

Max Milligan has left virtually no stone unturned in his explorations; whether recording the icy source of the Amazon, the Sacred Valley of the Incas, Fitzcarraldo's trade routes or the cactus forests of Apurimac, his passion and determination to do his subject justice shine through. With its magical photography and lively text, endorsed in the foreword by John Hemming (whose own definitive work The Conquest of the Incas was described in The Times as 'superbly vivid history distinguished by formidable scholarship'), Realm of the Incas is, quite simply, the culmination of Max Milligan's fifteen-year love affair with Peru's fabled Inca Region.