9. Lange Anna
The Lange Anna is a famous landmark of the small German island Heligoland, located in the north sea. The island used to be much larger but the waves slowly removed most of the rocks above sea level. The waves created beautiful formations such as caves and narrow peninsulas with arches at the bottom. When such an arch collapsed a sea stack remained. The 47 meter (154 feet) high is the result of the collapse of a natural arch in 1868. In the spring the rock is covered by sea birds who come to the rock to breed.