Russia's eastern Kamchatka Peninsula, which extends far into the Pacific Ocean, includes more than 150 volcanoes. While most are not actively erupting, many are considered dangerous due to their eruptive history and proximity to population centers and air travel corridors. This astronaut photo highlights the summit crater and snow-covered slopes of Avachinshy stratovolcano (2,741 m; 8,993 ft) as it pokes above a surrounding cloud deck. The volcano has an extensive historic and geological record of eruptions, the latest activity ocurring in 2008. To the southeast (image right), the large breached crater of Kozelsky volcano also appears above the clouds. Kozelsky is a parasitic cone, formed by the eruption of material from vents along the flank of Avachinsky. Photo courtesy of NASA.

The Kuril Island chain is built from a line of volcanoes, an island arc, that extends from Russia's Kamchatka Peninsula to northern Japan. Island arcs form along an active boundary between two tectonic plates, with one being driven beneath the other (subduction). Magma generated by subduction feeds volcanoes - and eventually volcanic islands - over the subduction boundary. Paramushir Island in the northern Kurils is an example of a large island built by several volcanoes over geologic time. This astronaut photograph shows the southern end of Paramushir Island after a snowfall. The western slopes of the mountains are brightly illuminated, while the eastern slopes are in shadow.Four major volcanic centers create this part of the island. Fuss Peak (image center left) is an isolated stratovolcano connected to the main island via an isthmus. Fuss Peak last erupted in 1854.The southern tip of the island is occupied by the Karpinsky Group of three volcanic centers. A minor eruption of ash following an earthquake occurred on this part of the island in 1952. The Lomonosov Group to the northeast (image center) includes four cinder cones and a lava dome.The most recent volcanic activity on Paramushir Island occurred in 2008 at the Chikurachki cone located along the northern coastline of the island at image top center. The summit of this volcano, 1,816 m (5,958 ft) above sea level, is the highest on Paramushir Island.Much of the Sea of Okhotsk visible in the image is covered with low clouds that often form around the islands in the Kuril chain. The clouds are generated by moisture-laden air passing over the cool sea/ocean water, and they typically wrap around the volcanic islands. Image courtesy of NASA.

The eastern side of the Kamchatka Peninsula juts into the Pacific Ocean west of Alaska in this enhanced winter satellite image. Snow-covered peaks and valley glaciers feed blue ice into coastal waters. The Kamchatka Peninsula is home to 160 volcanoes, 29 of which are active. The Volcanoes of Kamtchaka together form a UNESCO World Heritage Site. For other active volcanoes in Russia, see the Natural hazards-volcanism subfield in the Geography section. Image courtesy of USGS.

The prominent crimson streak in the center of this false-color satellite image represents the remains of a 50 km (31 mi) lahar (volcanic mudflow) that cut a strip of barren rock through rich vegetation surrounding the Anyuyskiy Volcano. The currently dormant volcano is the orange circular shape at the right end of the streak. Remote and largely inaccessible, the Kamchatka Peninsula is a rugged collection of towering volcanic peaks, steep valleys, active geysers, and wild, snow-fed rivers and streams. This volcano is part of the UNESCO World Heritage Site "Volcanoes of Kamchatka." For other active volcanoes in Russia, see the Natural hazards-volcanism subfield in the Geography section. Image courtesy of USGS.

Red dots mark the locations of fires burning in countries south and east of the Baltic Sea in this early April image. The scattered fires were probably set to clear land for agricultural purposes. The Scandinavian countries, Norway and Sweden, and Finland to the north of the Sea, are still blanketed in snow. From the left, the countries lining the Baltic on the south are Denmark, Germany, Poland, Russia (Kaliningrad), Lithuania, Latvia, Estonia, and Russia. Belarus forms the lower right corner of the image. Photo courtesy of NASA.

Measured by surface area, the Caspian Sea is the world's largest inland water body. It covers roughly 371,000 sq km (143,200 sq mi) and borders five countries. To the ancient Greeks and Persians, the lake's immense size suggested it was an ocean, hence its name. A large expanse of clear sky permitted this natural-color satellite image of the entire water body. The color of the Caspian Sea darkens from north to south, thanks to changes in depth and perhaps sediment and other runoff. The northern part of the lake is just 5 to 6 m (16 to 20 ft) deep. The southern end, however, plunges more than 1,000 m (3,300 ft). Just as the lake reaches a greater depth in the south, the nearby land reaches a greater height. The mountains of northern Iran line the southern end of the giant lake, and emerald green vegetation clings to those mountain slopes. In marked contrast to the mountains, sand seas line the southeastern and northern perimeters of the lake, and marshes occur along the lake shores in Azerbaijan to the west. Multiple rivers empty into the Caspian Sea, the Volga being the largest. Lacking an outlet, the Caspian Sea loses water only by evaporation, leading to the accumulation of salt. Although a lake, the Caspian is not a freshwater lake; the water delivered by the Volga River minimizes the lake's salt content at the northern end, but the Caspian grows more saline to the south. Kara-Bogaz-Gol is a saline inlet along the lake's eastern perimeter. Image courtesy of NASA.

When wind-driven clouds encounter obstacles, in this case islands, they flow around them to form large, spinning eddies known as Karman vortices. The Karman vortices in this high-resolution satellite photo formed over the islands of Broutona, Chirpoy, and Brat Chirpoyev (Chirpoy's Brother), all part of the Kuril Island chain found between Russia's Kamchatka Peninsula and Japan. Image courtesy of USGS.

Nicknamed "Dragon Lake," this body of water is formed by the Bratskove Reservoir, built along the Angara River in southern Siberia, near the city of Bratsk. At its inauguration in 1967, the Reservoir was the largest artificial lake in the world with a surface area of 5,470 sq km (2,110 sq mi). This high-resolution satellite image was acquired in winter, when the lake was frozen. Image courtesy of USGS.

The Lena River, some 4,500 km (2,800 mi) long, is one of the longest rivers in the world. The Lena Delta Reserve, shown in this enhanced satellite photo, is the most extensive protected wilderness area in Russia; it serves as an important refuge and breeding ground for many species of Siberian wildlife. The wave-dominated delta of the Lena River is 30,000 sq km (11,580 sq mi) making it one of the largest of its kind in the world. Image courtesy of USGS.

The Mayn River (on the left), seen here in a false color satellite image with a portion of the Anadyr River (on the right), flows through the far northeastern corner of Siberia. Both rivers carry a great deal of sediment and over time have created an amazing number of oxbow lakes. In this forest-tundra zone, both rivers remain frozen for 8 to 9 months out of the year. Image courtesy of USGS.

Vivid colors and bizarre shapes come together in an false-color satellite image that could be an imaginative illustration for a fantasy story. This labyrinth of exotic features is present along the edge of the Chaunskaya Bay (vivid blue half circle) in northeastern Siberia. Two major rivers, the Chaun and Palyavaam, flow into the bay, which in turn opens into the Arctic Ocean. Ribbon lakes and bogs are present throughout the area, created by depressions left by receding glaciers. Image courtesy of USGS.

The General Staff Building in Saint Petersburg's Palace Square was built in the 1820s. The arch commemorates the victory over Napoleon; it is topped by a bronze sculpture of Victory herself riding a six-horse chariot. Under the Russian Empire, the West Wing housed the General Staff, while the East Wing contained the Foreign Ministry and the Finance Ministry. The building is now part of the Hermitage Museum.

Saint Isaac's Cathedral in Saint Petersburg is the largest in the city. Its neoclassic exterior masks its sumptuously decorated interior.

The Peter and Paul Fortress in Saint Petersburg - built between 1706 and 1740 - surrounds the Saints Peter and Paul Cathedral (completed 1733), which houses the remains of almost all of the members of the Russian imperial family.

The Old Saint Petersburg Stock Exchange (white building) and one of its flanking Rostral Columns overlooking the inner harbor of the city.

The Cruiser Aurora anchored in Saint Petersburg Harbor. It was a blank shot fired from this ship that signaled the assault on the Winter Palace and launched the October 1917 Revolution.

The Bronze Horseman - an equestrian statue of Peter I in Saint Petersburg - has become a symbol of the city.

The former imperial Winter Palace in Saint Petersburg is now part of the Hermitage Museum.

The Alexander Column is a focal point of Palace Square in Saint Petersburg (part of the Winter Palace appears in the background). The single-piece red granite column was erected between 1830 and 1834 in grateful commemoration of Czar Alexander I who led the Russian victory in the war with Napoleonic France. The monument - the tallest of its kind in the world - is 47.5 m (156 ft) high and weighs some 600 tons.

The Cathedral of the Resurrection of Christ in Saint Petersburg - also known as the Church of the Savior on Spilled Blood - marks the location where Czar Alexander II was assasinated in 1881.

Peterhof Palace, near Saint Petersburg, sits atop a hill overlooking the Gulf of Finland. The Palace boasts a remarkable array of 64 decorative fountains, including a spectacular sculpture of Samson prying open the jaws of a lion as water cascades down terraced steps in the background. This was Peter I's summer palace.

Pastel colors highlight the central nave of the Saints Peter and Paul Cathedral in Saint Petersburg. The Cathedral is located inside the Peter and Paul Fortress and houses the remains of almost all Russian emperors (and empresses) from Peter I to Nicholas II.

Some of the beautiful architecture found in the interior of the Hermitage Museum in Saint Petersburg. Located on the River Neva, the museum occupies six buildings and reputedly houses 3 million works of art.

The Cathedral of the Resurrection of Christ in Saint Petersburg - also known as the Church of the Savior on Spilled Blood - was built on the site of the assassination of Alexander II. Its richly decorated façade and "onion domes" resemble those of the celebrated Saint Basil's Cathedral in Moscow.

The Chapel of the Iveron Icon of the Mother of God was built in 1781 over the Voskresensky (Resurrection) Gate in Moscow to hold a replica of a Greek icon brought from Greece in 1669. The Soviet Government removed the chapel in 1929 and the gate in 1931. Both were rebuilt between 1994 and 1996. The gate leads to Red Square (Saint Basil's Cathedral may be seen through the opening).

The Kazan Cathedral is a Russian Orthodox church located in the northeast corner of Red Square in Moscow. Originally constructed in 1636, the structure was destroyed in 1936 by the Soviet Government. It was rebuilt between 1990 and 1993 using detailed measurements and photos that had been preserved of the original church.

The Cathedral of Saint Basil the Blessed in Moscow is more formally known as the Cathedral of Intercession of Theotokas on the Moat. This Russian Orthodox church, located in Red Square, was erected in 1555-61 to commemorate the capture of Kazan and Astrakhan; it is located in the exact geometric center of the city. Since 1928 it has operated as a division of the State Historical Museum. The church was totally secularized in 1929; it is part of the Moscow Kremlin and Red Square UNESCO World Heritage site.

Close up of some of the colorful domes of Saint Basil's Cathedral in Moscow.

Saint Basil's Cathedral, Moscow in winter.

Christmas decorations in Moscow.

The Tomb of the Unknown Soldier in Moscow is a war memorial dedicated to Soviet soldiers killed during World War II. It is located in the Alexander Garden at the Kremlin Wall. First unveiled in 1967, a tombstone was added in 1975. The eternal flame emanates from the center of a five-pointed star located in front of the tombstone.

The Cathedral of Our Lady of Smolensk and its octagonal bell tower at the Novodevichy Convent in Moscow. Founded in 1524 to commemorate the capture of Smolensk from Lithuania, it became a convent for ladies of noble birth and was also used for a prison for female royals. Most of the current cathedral dates to the mid-17th century. After the Russian Revolution, the convent was turned into a museum. It was returned to the Russian Orthodox Church after World War II.