Photo Gallery: Caltech’s annual pumpkin drop

Over 400 pumpkins fell from the ninth floor during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Nov. 1, 2012 7:14 PM PT

After the streets were clear of trick-or-treaters and parties were winding down, a group of Caltech students were pushing crates of frozen pumpkins up the elevator in Millikan Library. As part of a Halloween tradition dating back to 1972, five students climbed a ladder to the tallest point of the roof and prepared to launch the pumpkins, frozen in liquid nitrogen, off the side of the nine-story building.

Students from Caltech watched over 400 pumpkins drop from ninth floor during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Rachel Gates prepares for Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Students prepare for Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Jomya Lei unloads over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Over 400 pumpkins fell from the ninth floor during Caltech's Annual Halloween Pumpkin drop, which took place at the Caltech's Millikan Library in Pasadena on Wednesday, October 31, 2012.

Nicholas Schiefer, right, helps Matt Coggon unload over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Annie Lee, center, and other students watch over 400 pumpkins drop from the ninth floor during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Jade Yan, from second left, Jomya Lei ad Rachel Gates unload over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Nichoas Schiefer unloads over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Michael Wheeler unloads over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Rachel Gates, from left, Jomya Lei and Nicholas Schiefer unload over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Nicholas Schiefer unloads over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)

Matthew Clark unloads over 400 pumpkins during Caltech’s Annual Halloween Pumpkin drop, which took place at the Caltech’s Millikan Library in Pasadena on Wednesday, October 31, 2012. (Cheryl A. Guerrero/Staff Photographer)