Geneva, Switzerland

Geneva sits where the Rhône leaves Lake Geneva, home to about 205,000 residents and the European seat of the United Nations, which hosts 38 international organisations. The 140-metre Jet d'Eau fountain, first installed in 1886 as a hydroelectric relief valve, ejects water at 200 km/h. The 12th-century Saint Peter's Cathedral hosted John Calvin from 1536, and the 1863 signing that founded the Red Cross took place here, with its museum across the river. Seven kilometres northwest, CERN operates the world's largest particle accelerator.