Disneyland -- known as "The Happiest Place on Earth" -- turned into a grim scene Sunday after a man was found dead outside the family theme park in Anaheim, California.

TMZ obtained video of cops standing around the 65-year-old man on Sunday afternoon after police say they were called to the scene for a "person in distress," who then fell unconscious outside Disneyland.

The Anaheim Police Department tells TMZ ... by the time officers arrived, they determined the man was already dead. Police say the man was a transient in the area and apparently died of natural causes.

While officers investigated, they closed the area around the south entrance of Disneyland for a period. 

Members of the Orange County Coroner's Office also responded and were seen loading the covered body onto a gurney and wheeling it away.

Shortly after, things went back to normal.