Today's Wallanlagen are the last remaining relics of the fortifications that once shielded Lübeck. In the 17th century, people began to replace the Medieval town wall with earth bastions to provide better protection against modern artillery. Because of funding problems, the fortifications were never completed and the city's whole east side remained unfortified. The bastions of Lübeck never had to stand a siege and had long lost any military function in the second half of the 19th century, when building the railroad, the new Holstenhafen harbor and the Elbe-Lübeck-Kanal required tearing down most of the walls. Only some parts have remained, covered densely with trees and with trails for nice walks. From the wall top near the Kaisertor, the view of the cathedral is marvellous.