The heads are part of Olmec civilization of ancient Mesoamerica. The common reason why they made this because of their religious belief.
<u>Explanation:</u>
The Olmecs are famously known for the statues they carved: 20 ton stone heads, quarried and carved to commemorate their rulers. They are the first known civilization in America and the first to have this unique kind of construction.
Like most of the early Mesoamerican cultures, Olmec also believed in three tiers of existence: the physical realm they inhabited, an underworld and a sky realm, home of most of the gods.