And here I was on it, the silver water lapping the side of the boat as we poled away from the dock in the predawn light.

I had come to Egypt, as most tourists do, to see the pyramids, the mosques and palaces and souks, and the ancient temples and tombs strung like gems along the Nile. But it was the river that really spoke to me.

My first glimpse might not seem so awe inspiring: On a hot and jet-lagged afternoon the lazy river appeared hemmed in by Cairo's jammed boulevards and modern buildings, its color matching the hazy gray sky where pollution blotted out the searing blues of North Africa.

No grand river traffic took my breath away, no exquisite bridges or soaring architecture or wondrous islands rose to demand my attention. It was simply the Nile, passive on a normal day, flowing as it has for so many thousands of years.

The Nile. Seeing it was like catching sight of other great rivers of the world for the first time: the Amazon, Brahmaputra, Ganges, Mississippi, Rhine, Zambezi.

Like many of these others, the Nile is a river of the imagination, impressive even in its languid passage through Cairo because of what we bring to it: our sense of history and the Nile's contributions.

The Nile is the world's longest river, flowing 4,160 miles (500 miles farther than from New York to Paris) from the highlands of Rwanda and Ethiopia through Sudan and Egypt before emptying into the Mediterranean Sea.

Egyptian society was essentially stable for 3,000 years because of the reliability of the Nile's floods and the ready supply of water for irrigation.

Without the Nile, there would have been no ancient Egypt. And the Nile continues its good work today, providing sustenance for a population exponentially larger than it was in ancient times.

Cairo today has upward of 18 million people, almost a quarter of Egypt's total population.

The city is ancient by the usual standards (1,000-plus years old), but a spring chicken compared with the Giza Pyramids; the temples at Luxor, Karnak and Abu Simbel; and the tombs in the Valley of the Kings, where King Tutankhamun was buried.

It is also a megacity with modern challenges and modern mores interwoven with traditional life.

That morning the sail hung limply from the single mast of the felucca, the kind of traditional Egyptian sailboat that has plied these waters since, well, since about the dawn of man.

With barely a hint of breeze I wondered how Mahedui would get us under sail.

All around, the world was still, and that was a rare thing indeed for modern Cairo.

The evening before, I'd taken a walk along the Nile, past these same docks, in a cacophony of traffic beeps, honks, blares and shrieks, both mesmerized and appalled by the crush of cars, the rising heat, the smell of vehicle exhaust and clouds of smoke.

As the dawn light shifted from gray to rosy pink, the sail caught a bit of breeze and we moved out into the river. Mahedui smiled as if to say "I told you so," and the boat progressed upstream as subtly as the light changed. The rising sun gradually parted the haze and cast a golden glow on the river to light up a two-person scull skimming across the water.

The oarsmen, er, women, wore head scarves and sweaters over their traditional Egyptian galabias. Then an eight-person scull with a coxswain appeared, again all women, all but one wearing a head scarf. And far upstream, in the shadow of Cairo's high-rises, two people in a rowboat with long oars like planks fished the river as their ancestors had done for thousands of years.

In addition to head-scarved sculling crews, I later saw camel-driving touts at the Giza Pyramids texting business associates.

Most of the souvenirs found in the main areas of the Khan el-Khalili bazaar, Cairo's oldest marketplace that dates to medieval times, are made in China.

Millions of people live in the ancient cemetery called the City of the Dead, where a necropolis has become a metropolis. Cars, taxis, trucks and buses share city streets with horse buggies and carts, all contributing their own forms of charm and congestion to the general atmosphere.

Outside the Egyptian Museum, children clamber over sculptures, and women in all manner of traditional dress pose for family photos. The laughter and smiles confirm that we are not so different: We are all modern, all ancient in our bloodlines and traditions.

Taking in the view

Outside Cairo, the Nile courses through another world, a place in many respects unchanged fom centuries past. Rowboats ply the flat waters carrying fishermen. Children chase bullocks in the fields by the water's edge.

Families spill out of stick shelters to harvest cane and stack it on small barges to be carried to market.

Donkeys stand motionless, awaiting their burdens. For miles and miles, the landscape spreads out low and flat and green, testament to the river's gifts.

I took all of this in from the deck of a Nile cruise boat, probably the best way to see Egypt's ancient sights.

These floating hotels cruise between Luxor and Aswan, three days downstream or four days upstream, and all offer tours of the world-renowned sites of Luxor, Karnak, the Valley of the Kings, Edfu, Kom Ombo, and the temples at Aswan.

All of these sites are worth seeing if only to be awed, to appreciate anew the sophistication of the ancient Egyptians and the ingenuity of humankind. The more adventurous can sail in a felucca on the same course, taking longer, especially if going upstream.

Farther south, almost to the Sudan border, lies Abu Simbel, the rock-cut temple dedicated to Ramses II, who was also known as Ramses the Great because of his long reign and building on a monumental scale up and down the Nile.

Flying here from Cairo or Aswan is the most efficient way to see it, and like the other main sites, it's well worth the effort.

The temple sits on the southern edge of Lake Nasser, the vast body of water (the world's largest artificial lake at more than 300 miles long) created with the completion of the Aswan High Dam in 1971.

In the early morning light, I walked with scores of others through the sand toward the Great Temple of Abu Simbel and its four colossi.

But before I reached it, my gaze drifted to the horizon where the low sun washed a pale blue sky and the opalescent waters of the lake, a near-mirage of blue rising from the Nubian desert, cool water against the searing sand, a thin margin between life and desolation.

Lake Nasser looked as if it had been there forever, and the fact that it hadn't seemed almost as marvelous as the fact that the Great Temple would have been submerged by the lake without an extraordinary UNESCO-led relocation project that carved it up and reassembled it on higher ground to save it from inundation.

Rescue of the past

More than 20 ancient monuments were saved this way, the second largest being the Temple of Philae in Aswan.

The temple is dedicated to Isis and was an important pilgrimage site from the fifth century B.C. to the sixth century A.D., then during the Victorian period drew many tourists from Europe.

Today, it stands on an island similar to its original site on Philae. Tours of the Temple of Philae come and go via excursion boats crossing the short waterway between the island and mainland.

On our return, our boat lost power. Another tourist boat roped us up broadside and towed us in while we chatted with our new neighbors, an Egyptian family.

A man with his wife, three young children and mother-in-law were taking in the sights of their heritage. The mother-in-law sat proudly on her bench in full head scarf and flowing black galabia. To complete her ensemble, she wore wraparound sunglasses and a sun visor to match her grandson's: a yellow and red plastic lid topped with a cartoon rendition of a mouse and the words "Tom and Jerry."

Before sunset, I was back on a felucca on the Nile in Aswan. The Western Desert pushed right up to the water as if to remind us that the great river was the only thing between us and the unforgiving expanse of the Sahara.

And as if we all understood the message, we sailed on, back and forth, amid dozens of feluccas and an armada of excursion boats packed with Egyptian tourists, music blaring, crisscrossing each other's wakes.

Whether we knew it or not, we were all celebrating our tenuous grasp on life in this modern time, linked to each other and to past eons by our shared humanity. And, of course, linked also by the lifeblood waters of this ancient and modern river.

Larry Habegger is executive editor of Travelers' Tales, author of World Travel Watch and editor in chief of Triporati.com.

This article appeared on page M - 1 of the San Francisco Chronicle