A must place to visit on your way to or from Eilat. In fact, a reason to go to Eilat.
This is one of the best nature sights in Israel. The special stone formations, the stone colors (mainly red but also yellow, orange, grey, brown, or black), the lake and the ancient copper mines make this place a great attraction.
You should plan to make this a whole day trip, between the sights you have to drive with the car. Also, take a lot of water with you as you are entering desert terrain.