The open-top City Bus Tour is a fun way to spend half a day. The commentary is in eight languages (through free headphones). Pick it up just outside the marina to the south on Avenue Maritima, and the tour allows you to jump off and explore before continuing on the next bus, normally 30 minutes later. Tours run from 0930 to 1745 daily and the last bus is a great nighttime tour of the City. Buy your ticket on the bus (15E).