San Antonio trench thought to be pre-Alamo Mexican bunker

Historians say an old trench discovered in San Antonio might have been used by Mexican soldiers as fortification against Texan rebels during a siege that preceded the Battle of the Alamo.

Workers found the trench off Main Plaza, San Antonio's historic city center, as they were digging up the street a couple of weeks ago to install a storm-water line, city officials said.

Archaeologists think the trench was built by Mexican forces under the command of Gen. Martin Perfecto de Cos. From October to December 1835, the city was under siege by Texas rebels in an early campaign of the Texas Revolution.