Alexanderplatz is a large open square and public transport hub in Berlin city centre, near the river Spree and the Berliner Dom. Berliners often call it simply Alex. Originally a cattle market, it was named in honour of a visit of the Russian Emperor Alexander I to Berlin on 25 October 1805. It gained a prominent role in the late 19th century with the construction of the station of the same name and a nearby public market, becoming a major commercial centre. Its heyday was in the 1920s, when together with Potsdamer Platz it was at the heart of Berlin's nightlife, inspiring the 1929 novel Berlin Alexanderplatz (see 1920s Berlin) and the two films based thereon, Piel Jutzi's 1931 film and Rainer Werner Fassbinder's 15 1/2 hour second adaptation, released in 1980.