shake, rattle and demolish

Tae Bo workout sent skyscraper shaking

Seventeen people performing a vigorous Tae Bo workout caused tremors that forced the evacuation of a South Korean skyscraper earlier this month, the building's owners say.

"It just happened to be that the vibration cycle caused by Tae Bo collided with the vertical vibration cycle unique to the building." [...] The action amplified the building's vibration and caused the shaking.