144km (89 miles) NE of Amsterdam; 51km (32 miles) E of Leeuwarden

Groningen, the capital city of Groningen province, is commercially and industrially important, and sits atop one of the world's largest natural gas fields -- holding 2.7 trillion cubic meters (95 trillion cubic feet) of the stuff, if you must know. Cars are banned from the Old Town, which is enclosed by a moat. Part of the center city was destroyed during World War II, but much of its medieval and 16th- and 17th-century heritage survived and has been preserved. The University of Groningen was founded in 1614, and a student population of 45,000, from a total city population of 185,000, gives the town a lively character.