You'll find a preserve called the Prokop Valley in the south-west of Prague. It's extremely protected - this is where the remains of woolly rhinoceros and mammoths were found.
You will find it in Prague 5, between Jinonice and Zlíchov, to be more precise. Besides the ponds, quarries and rock formations, this place offers its visitors many historical points of interest. Walk back in time. There was once evidence of prehistoric peoples and trilobites found here, so with some luck, you'll make another revolutionary archaeological discovery. If you don't happen to, never mind, you can still admire the beautiful nature, walk atop Děvín Hill or explore the Butovice former fortified settlement, then take the educational trail and walk through other parts of the preserve.
As you walk around, be careful, though. The area has been well protected ever since the communist era. The scene from the film Cosy Dens springs to mind - when two police officers watch out for a man with a leather bag, riding a motorcycle. The order was clear - he would not pass, no matter what. What happened to him? You're welcome to find out for yourself, we don't want to ruin it for you.