Situated in the heart of the Mercantour National Park, the Vallee des Merveilles (or valley of wonders) is famous for its large number (over 40 thousand) of rock engravings dating from the Bronze Age (from 3300 to 1200 BC). These engravings are spread out over a large area, and are accessible through guided tours from June to September.
Tende is the best place to start; guided tours start here also.
You can also discover some of the engravings on your own, by following the signposted tracks; start your discovery at Lac des Mesches, near St. Dalmas de Tende.
I tried to go there once in early April (see pictures below) - big mistake, as despite some warmer weather, there was still loads of snow, which made walking near impossible and of course also hid the engravings.
On the positive side, it was still a beautiful hike!
Early June is a much better time, as pictures below attest.
In fact, if you want to be able to properly see the engravings in the area, June through to September is the best period.
For more information visit tendemerveilles.com .