United States
A 19th-century canal and towpath that runs west from Rock Creek between M St and the Potomac River, and parallels the river 185 miles to the mountain town of Cumberland, Maryland.
Four locks lift the water level through Georgetown; a "living history" canal boat drawn by two mules carries passengers between spring and autumn through a lock or two for about a mile upstream, then back. A lot of folks just watch the locking operation and walk along the towpath.
It's a wonderful and pastoral contrast to the shopping and nightlife of Georgetown, itself an 18th-century town that was absorbed into Washington DC.
The boat is found between Thomas Jefferson Place and 30th St NW; www.nps.gov/choh/
Take the kids to the Air and Space Museum and take in an IMAX movie there.
Sixth Street & Independence Avenue, SW, The Mall & Tidal Basin; Tel: 1-202 357 2700; L’Enfant Plaza Metro; Open: Sept-May 10am-5.30pm daily; Admission: Museum free, Planetarium $8; www.nasm.si.edu/
Search Been there