This beautiful triple arches is located on the praia dos Tres Irmaos (Three Brothers Beach) in Algarve province of Portugal. The thrid opening is a small sinkhole, natural well eroded from the top of the cliff open in the sea or beach (depending the level of the tide). These sinkholes are numerous on the rocky coast of Algarve. It is unique in geologic formation though this area shows many spectacular large and deep natural well. Note that left top and the right side of the arch rock was recently defaced by bulldozer work to preserve sunbathing from the rock fall... no comment.