LINCOLN, Neb. (AP) — Two high-rise dormitories at the University of Nebraska-Lincoln have crashed to the ground in a planned implosion.

The university demolished Cather and Pound halls simultaneously Friday in about 10 seconds. Crews spent several weeks placing dynamite into support columns on select floors and wiring charges to ensure the detonation went as planned. Roughly 500 pounds (225 kilograms) of dynamite was used.

Preparations began in May, when the university began removing windows, heavy furniture and mechanical parts from the dorms.

Engineers estimate each building weighed 200 million tons (180 million metric tons). The dorms had housed thousands of university students since 1963, but were outdated.

University housing director Sue Gildersleeve says imploding the buildings proved more feasible than destroying them with a wrecking ball. The implosion was timed to coincide with the university’s holiday break.