Grgos cave is at the entrance of the village Otruševac, 5 km from Samobor. The cave has two chambers, and the altitude difference is 19 m. The cave has many stalactites and is 30 m long. Josip Grgos discovered the cave in 1973 when he was mining for rocks used in processing lime. The new cave was discovered in 2007, with three new chambers, 130 m long. There is a path and electric lightning along the cave, which was pronounced a protected geomorphologic natural monument.