Which Spanish fortification outside Santiago was attacked at El Caney?

The Spanish fortification outside Santiago attacked at El Caney was Fort El Viso.

El Viso was a key Spanish strongpoint defending El Caney, a settlement northeast of Santiago de Cuba. The position stood on elevated ground and formed part of a defensive network that included blockhouses, trenches, and other fortified points. Its location made it important for protecting the approaches to Santiago and for delaying an American advance toward the San Juan Heights.

During the Battle of El Caney on July 1, 1898, U.S. artillery under Captain Allyn Capron concentrated on El Viso after earlier attacks failed to break the Spanish defenses. The guns eventually breached the strongpoint’s walls. Infantry from the 12th and 25th U.S. Infantry then attacked and captured it; Private T. C. Butler of the 25th Infantry is credited with being the first American soldier to enter the blockhouse.

The fort is easy to confuse with Morro Castle, a much more famous fortress associated with Havana and the entrance to its harbor. El Viso was instead a smaller field fortification tied directly to the defense of El Caney. Its capture helped unravel the Spanish position, although the battle continued until the surviving defenders withdrew.