Cas′pian Sea, an inclosed inland sea or great salt-lake, the largest in the world, lies on the boundary between Europe and Asia. It is bounded on the south by Persia and on the north by Russia; with the Caucasus Mountains on its westward and the transcaspian territory on the east. Its length from north to south is 700 miles, and its breadth varies from 130 to 270 miles. Its total area is estimated at 170,000 square miles. On the east side, especially, there are several bays and peninsulas. On the south a low, flat plain, from 15 to 20 miles in width, leads to the lofty range of the Elburz Mountains; while the north is bordered by great steppes. The surface of the Caspian is 97 feet below the level of the Black Sea and 248 feet below that of Lake Aral. It is probable that all three bodies were once connected. The Caspian has no tides, but violent storms make navigation dangerous. Its level varies much at different seasons. In the middle it is divided by a submarine ridge, a continuation of the main Caucasus chain, into two deep basins. The greatest depth found in the northern basin is 2,526 feet and in the southern 3,006 feet. A number of large rivers empty their waters into the Caspian, of which the greatest is the Volga. The sea abounds in fish, and valuable fisheries are carried on, especially for sturgeon and salmon. By a canal uniting the upper tributaries of the Volga with those of Lake Ladoga and the Dwina, the Caspian is united with the Baltic Sea. The sea is now surrounded on three sides by Russian territory, the southern shore still remaining Persian. The Russians maintain a flotilla on the Caspian Sea, and lines of steam-packets ply upon it.