The ancient Mayan city of Tulum is a complex of several buildings. Tulum means "wall." It encompasses the entire settlement that used to be a commercial hub.
There are two very long and quite steep ramps from the entrance. Not easy ones for a wheelchair user by himself. Better with help.
The site is quite flat and the surface is mostly ravel. Getting close to the buildings is partial, but they are trying to improve the accessibility.
However, it is worth seeing the famous El Castillo pyramid and other interesting sights here.
Thanks for this partly accessible travel tip, Tonya Graves.