In the late 19th century, the main course of the River Danube was straightened to allow larger vessels to dock. A parallel channel was cut in the 1970s, creating a long, thin artificial island, officially known as "Donauinsel," though often called the Copa Cagrana after Kagran, the 22nd district in which it is situated. The original course of the Danube, to the east of the Neue Donau, was then used to create the semi-circular nub of land known as Kaisermühlen, home to Vienna's UNO-City. To be honest, the Donauinsel (measuring 20km by just 200m) is pretty bleak; nevertheless, it is a paradise for cycling and rollerblading. In summer, the Viennese flock to the beaches here. At night, there are numerous bars, discos, restaurants and food stalls, centered around the Donauinsel underground-station.