The gorges were carved into the limestone over 6 million years. The sand at your feet testifies to the fact that this area was once part of the seabed.
The Combe de Lourmarin is a winding gorge between Apt and Lourmarin. From Apt it's a really nice descent to do. From Lourmarin, the climb is about 10km with an average gradient of 4%.
The best thing are the hairpin bends on the descent, great views, wonderful route with lots of photo opportunities, especially climbing rocks - unfortunately far too short.