April 27 marks not one but two highlights of the school year at the Massachusetts Institute of Technology (MIT) in Cambridge: the last day students can drop out of classes without having them appear on college transcripts, and the yearly Piano Drop

The event only lasts a few seconds, but always draws a big crowd of people ready to record photos and video of the event and eager to take home a souvenir. The 40-year old tradition of throwing a piano off the roof of MIT's Baker House so that it lands on a second piano, smashing both to bits, started with a fluke.

It started 40 years ago when some students in Baker House had an extra piano and wanted to get rid of it, a student involved in the organization of the event told ITN News.

The upright piano is rolled down a makeshift ramp off of the roof, and lands with a thud and a short twang as it crushes the second piano and the tightly strung piano strings snap and break.

According to NBC, around 200 onlookers gathered to watch the upright piano crash into the baby-grand positioned six stories below. Afterwards onlookers scrambling for a prize to remember the crash (keys, hammers, strings or just bits of wood).

Although the first piano was dropped off the roof of Baker House four decades ago, the tradition was observed only sporadically until 2006 when it officially became an annual event, according to Michael Plasmeier, who organizes the dorm's student government.

No piano has ever fallen on anyone's head, organizers say.

It's done very safely, and it's done with coordination with MIT security and emergency management office, and we set up a barrier well away from the piano, and then the people on the roof receive training from the security and management office, Michael Plasmeier explained.

The Piano Drop is always one of the highlights or maybe lowlights, as the case may be, and it's a lot of fun, said Jeffrey Hoffman, the housemaster of the dorm to NBC. The students basically run it, we're just here to see nobody gets hurt.

You're waiting for that twang when it hits everything goes boing! an onlooker told ITN. It's fun to see a piano hit a piano, you don't usually see that. It was pretty cool.