The most difficult ge­og­ra­phy of Russia riddles

Vistula is the longest of the Baltic Sea affluents, but its mean discharge of 1080 m3/s is less than half of Neva (2500 m3/s). Other major Baltic Sea effluents are Daugawa nad Neman (both 678 m3/s).

There are about 6 million speakers of Tatar in Russia, mostly in the Russian Republic of Tatarstan, where it is the official language along with Russian. The language is used by Volga Tatars, not to be confused with the Crimean Tatar Language, to which it is related but with which it is not readily mutually intelligible.

Two characteristic peaks of Mt Elbrus have two volcano craters. The eastern peak has an enormous crater 250m in diameter.

Russia is by far the largest country in the world, and 45% of its area is forested. That gives almost twice as large forested area as in Brazil.

The Jewish Autonomous Oblast is a federal subject of Russia in the Russian Far East, bordering China. Soviet authorities established it in 1934 as the result of Stalin's nationality policy. The Jewish population peaked in 1948 at around 30,000, about one-quarter of the region's population. Today only about 4,000 Jews remain in the region - but it is still officially named as Jewish.

Lake Baikal is the deepest and the oldest lake, at least 25 million years old. It was formed as an ancient rift valley. Due its age, size and isolation, it hosts about 1000 endemic species of plants and animals (which can be found nowhere else in the world).

The Volga is the largest river in Europe in terms of length, discharge, and watershed. The river has a symbolic meaning in Russian culture and is often referred to as Volga-Matushka (Volga-mother) in Russian literature and folklore.

All of the islands are under the Russian jurisdiction, but Japan claims the two southernmost large islands (Iturup and Kunashir) as part of its territory, as well as Shikotan and the Habomai islets, which has led to the ongoing Kuril Islands dispute.

The Volga Delta has grown significantly in the past century because of changes in the level of the Caspian Sea. In 1880, the delta had an area of 3,222 km². Today the Volga Delta covers an area of 27,224 km² and is approximately 160 km across.