On Monday, the world lost a comedy legend.

Harold Ramis, the comedic actor, writer, and director most well-known known for his role in 'Ghostbusters' (and his writing and directing credits on 'Groundhog Day,' 'Caddyshack,' 'Animal House,' 'Analyze This' and more), died at the age of 69 due to a rare vascular disease. 

Though Ramis' biggest hits may have occurred in the '80s and '90s, younger fans may recognize him for his role as Seth Rogen's dad in 2007's 'Knocked Up.' He also wrote and directed the 2009 Jack Black/Michael Cera comedy 'Year One' and worked with Steve Carrell on 'The Office.'

While a comedy, Ramis' biggest hit, 'Groundhog Day,' is much more than that. The plot of the film -- a weatherman forced to relive the same day until he gets it right -- has gone on to become the basis of many philosophical and religious discussions, according to CNN. It's clear that Ramis' legacy lives on, but not just in film. He is survived by his wife, Erica Mann Ramis, and their three kids.

Hollywood has been left devastated by the loss, and far and wide, celebrities -- many of whom looked up to Ramis as the hero behind their favorite films -- have taken to Twitter to express their sadness and recall the joy that Ramis had brought to their lives via film.