Inner Sea

The area known as the Inner Sea is divided into the eastern Sea of Dreams and the western Sea of Dusk. The waters here are magically calm and peaceful. Trading ships from the Inner Kingdoms ply these placid waters bearing horses from Ellyrion and the magical wares of Saphery to Lothern and returning laden with the wares of half the world. Many pilgrims take passage on these seas en route to the Shrine of Asuryan in the Sea of Dreams and the Earth Mother in the Sea of Dusk.

Once a year the sacred white barges of the Phoenix King and the Everqueen ply the waters to their respective shrines. These stately craft are an awe-inspiring sight, each carved from the bole of single great ironwood tree. Each ship is built for the coronation of the ruler and on his or her death bears them off to the Isle of the Dead to rest at last with the ancient rulers of Ulthuan. As the barges plough the blue waters nothing slows their stately progress, no wind fills their sails, no hand guides their tiller. They follow the lines of power that run through the Inner Sea to their destination. In times of great trouble, the ghostly outlines of the White Ships can be seen sailing the waters of the Inner Sea.

Source
Warhammer Armies: High Elves (5th Edition) -- pg. 7