Caracas, near the train station.
Remarkable footage of the incident shows the heavy cranes teetering at the edge of the cliff before an ill-judged manoeuvre sends them tumbling over.
Moments before, one of the men can be heard telling his workmates that he is attempting a "dangerous manoeuvre" but is "doing an excellent job."
The video appears to show the first crane slam to the ground, creating a chain reaction that seems to pull the second crane down into the pit.
Two people were injured as a result of the crane crash.
The municipal president has visited the scene and has ordered the construction company, Odebrecht, to investigate the incident.
