Aerial view of Becán earthworks from the Southwest
Fig. 1. Aerial view from the southwest, showing cleared section of the defenses. Causeway I and Structure XXIII are in foreground, with Structure IV at center. For scale note the trucks in the parking lot near Causeway VII in the lower foreground.
"The earthworks discovered by Ruppert and Denison in 1934 represent massive fortifications erected during the Early Classic period, possibly in response to political inbalances caused by an intrusion of foreign elements from the central Mexican highlands...The fortifications of Becan represent the earliest clearcut evidence for large-scale military activity in the lowlands."
Webster, Defensive Earthworks at Becán, p. 3