After seeing this place on pictures, I decided to go there with a friend. We were lucky we could go by car and could park at just a few 100 meters of the entrance. This place used to be a quarry, but is now more a touristic spot. You don't have to pay to get in, but they do check you bags for security. Maybe it's best to ask some information when getting in. There is a path going all the way up the hill and around the lake. You will get one of the best view on the other side, so it is recommended to go. Make sure you take something to drink (like tereré), 'cause you might need it!