Its ashamed some people do not understand or appreciate our historic landmarks. Massachusetts police are investigating a recent graffiti spree that left a number of these historic landmarks in Plymouth vandalized. We are just days away from the 400th Anniversary Celebration of several National monuments – including Plymouth Rock. As you likely know, the rock commemorates the 1620 arrival of the Mayflower carrying pilgrims to North America. Plymouth town manager Melissa Arrighi says the community is heart broken and that steps have taken place to clean up the landmarks so that America can celebrate all that these monuments stand for.