Humberto Vidal explosion: Thirty-three people die when a Humberto Vidal shoe shop in Río Piedras, Puerto Rico explodes.

The Humberto Vidal explosion was a gas explosion that occurred on November 21, 1996 at the Humberto Vidal shoe store in Río Piedras, Puerto Rico. The explosion killed 33 and wounded 69 others when the building collapsed. It is one of the deadliest disasters to have occurred on the island.

Río Piedras is a highly urbanized commercial and residential district in San Juan, the capital municipality of Puerto Rico. Adjacent to the Hato Rey business center and concentrated in the barrios of Pueblo, Universidad, Hato Rey Sur, El Cinco, and Monacillo Urbano, it is about 4 to 7 miles from the Old San Juan historic quarter, Condado and Isla Verde resort areas, and SJU airport. It has been the home of the main campus of the University of Puerto Rico since 1903, earning the popular name of Ciudad Universitaria. The largest health institution in the archipelago, the Centro Médico de Puerto Rico, is also located within its limits. Named after the river that flows through it, the Río Piedras, the district was the downtown center of a former municipality with the same name that was merged into San Juan in 1951.