Shell Grotto at Margate (UK) In 1835 Mr James Newlove lowered his young son Joshua into a hole in the ground that had appeared during the digging of a duck pond. Joshua emerged describing tunnels covered with shells. He had discovered the Shell Grotto.
Gorges de l'Areuse, Switzerland The Val de Travers is a Jura mountain valley perpendicular to the main valleys (hence the name). The river Areuse has cut itself steeply through the soft limestone and clay sediments. It's one of those Roman bridges too.