The area is steeped in history being part of the battlefield of the Hundred Years War. Many of the castles, villages and towns were built by the English (a large part of the area became British owned in the 13th Century on the marriage of Eleanor of Aquitane to Henry II). The mediaeval new towns are known as Bastide towns and have remained largely unchanged. They are often in stunning hilltop locations built around arcaded market places - some of the more beautiful being Monpazier, Monflanquin, Tournon d'Agenais, Puymirol, Lauzerte. Richard 'Coeur de Lion' the Lionheart sallied forth from a, now ruined, hilltop stronghold in Penne d'Agenais.
Of the larger towns Moissac is of great architectural interest having a Romanesque abbey and cloister, Agen and Cahors (sited on a loop of the river Lot, which is spanned by the 14th Century Pont Valentre a remarkable mediaeval military bridge - see picture below) & Villeneuve-sur-Lot are some of the lively towns to visit.
And don't miss the Chateau at Bonaguil (see picture above) is one of the finest examples of 15th Century architecture or the magnificent Chateau at Biron. Or the prehistoric caves (including the Sistene Chapel of painted caves), the troglodyte habitations, museums, zoos and of course the Pink city of Toulouse (a cosmopolitan and vibrant university city) and the grander Bordeaux.