Cahors

Cahors is a charming old town (dating back to the Roman era) on the Lot River. Start with the really impressive 14th century bridge, the Ponte Valentre. A sturdy stone bridge, with three crenellated towers, it withstood attacks during the Hundred Years War.

South of the bridge (east side of the river) is the Fontaine des Chartreux, a sacred spring since Roman times (you can see bits of the Roman ruins).
Feel like a cruise on the Lot River? Pick up boats (bateaux mouche or gabare) at the quai Valentre.
A farmer's market is held Wednesday and Saturday on the cathedral square (place Chapou). Stop to pick up cheeses, melons, and the local Lot bread.
L'Archipel - Cahors has a really fine municipal water park on Cabessut Island. The water park, open June-Sept., has big swimming pools, water slides, kiddie pool, and picnic area.