La Ventana (The Window) is in Parque Provincial Ischigualasto, also known as Valley of the Moon, in San Juan Province in northwest Argentina. The park is a UNESCO World Heritage Site. The park can only be visited by taking a guided tour by a park ranger - you drive your own vehicle. There are five stops and the fourth one is The Submarine, the rock towers seen through the arch in the photo. Unfortunately access to the arch is restricted because a few years ago a women fell though a smaller arch alongside and died. La Ventana has a span of about 15 feet and a height of about 6 feet. Photo by Ray Millar.