Pech Merle is one of the greatest monuments of prehistoric art and should be near the top of your list of sites to visit. It features some of the oldest artwork in a cave open to the public: the famous spotted horses are 29,000 years old. This is a companion cave to Cougnac; they are from the same era and the artwork is similar. Both caves can be visited on the same day and they are about an hour's drive apart. Pech Merle is about 1.5 hours north of Toulouse and about 1.5 hours southeast of Les Eyzies.
Pech Merle is quite a large cave and has many open spaces with good lighting. The tour lasts an hour and focuses on artwork and geological formations, so it satisfies both types of visitor. There are engravings and drawings of horses, mammoths, and many other animals. There are also some good human figures, which are rare in cave art. The most famous is the "killed man" figure with spear-like lines stuck into it, similar to the ones at Cougnac.
There is also a small museum showing some of the artifacts that have been excavated there and at other caves, along with an introduction to paleolithic art and life. There are also depictions of some animal drawings that are not shown on the tour.
Guided tours only, limited to 700 people per day, reservations are accepted. English tours are not offered every day, so check the reservation link on their website. In July and August you should make a reservation.
This cave is not too strenuous, but there are some stairs down to the cave, some stairs in the cave, and the ground in the cave is uneven or wet in a few places. Click here to see more information on the physical requirements for the tour.