The Grottes and Canyon de Saulges is an amazing place to visit, between Laval and Le Mans.

There are 2 underground caves with a spectacular display of stalacmites and stalactites. Part of the site is still an on-going archeological excavation, revealing remains of prehistoric man, and there are still vestiges of cave paintings.
La Grotte de Rochefort will leave you breathless. You descend 17m and are ultimately 35m below ground level. The ‘Giant’s hand’, a gnarled stalagmite reaches out as if to grab you! Your reward for reaching the bottom is a view of a luminous lake whose crystal waters shelter tiny albino shrimp.
Heading towards the light as you emerge from the cave, it is impossible not to be enchanted by your surroundings.

It's also a rock climbing spot and there are hiking trails to explore the area.