Marilyn Monroe -- Grave Site BOMBARDED with Marilyn Memorabilia

Celebrity grave sites are often marked with flowers and photos to mark a birthday or death anniversary ... but the memorial park that is home to Marilyn Monroe says they were completely overrun yesterday by fans of the late blonde bombshell.

A spokesman for the Westwood Village Memorial Park Cemetery tells TMZ there was an "abnormally large" crowd on Friday -- her 86th birthday -- with people leaving items such as cards, photos, candles, statues, and flowers.

The spokesman tells TMZ they usually try and leave the items on the grave site for as long as possible (until they start to overrun neighboring spaces) but the clean-up yesterday for Marilyn went down faster than usual.

The Westwood Village Memorial Park Cemetery is also the final resting place of Janis Joplin, Peter Falk, Rodney Dangerfield, Natalie Wood, Farrah Fawcett ... and the list goes on.