Valencian Community

Alicante

Spain

Attention: this dive can be very dangerous if you pass the entrance into the interior of the subterranean river. There the current is very strong.
The mix of sweat water with salt water is amazing.

In the south end of the car parking in Playa de Moraig there´s a cave, the "Cueva de los Arcos" where you dive trough a tunnel to the open sea. Swim south, near the wall, until you find an entrance into a cave: that´s the Cueva del Morach, a subterranean river. 

Cueva del Morach is also known as Cova de moraig.