El Gasco Dam

The El Gasco Dam is an unfinished ruin located on the Guadarrama River at the confluence of Torrelodones, Galapagar, and Las Rozas de Madrid. It was constructed in the last third of the 18th century by the French engineer Carlos Lemaur as part of the failed [Guadarrama Canal project](https://www.comunidad.madrid/en/patrimonio-cultural/presa-gasco-canal-guadarrama), which aimed to create a navigable waterway connecting the Tagus and Guadalquivir rivers to the Atlantic Ocean. Today, the ruins are a popular destination for hiking trails in the Community of Madrid.

Galapagar, Madrid, Spain