12 reactions | A century-old Caltech tradition, Ditch Day is one of the culminating events of the academic year. The day is defined by the “stacks” that seniors create for their younger classmates, challenging them to solve themed puzzles that often entail funky costumes, games, and unconventional activities across campus. This year, Ditch Day stacks included raft-building, scavenger hunts, ethical dilemmas, and more. | Caltech | Facebook