An aerial video captured the moment fire rapidly spread across the dome of the Olympic velodrome at Rio de Janeiro Olympic Park at 4:17 on 8/4. The blaze quickly expanded, engulfing half the dome and emitting thick smoke.

Fire engulfs Brazil's largest velodrome in Rio de Janeiro on 8/4. *Video: X/ViralBase*

Rio de Janeiro fire officials dispatched 20 fire trucks and 80 firefighters to the scene. The blaze was brought under control by morning, leaving a portion of the dome charred, but causing no casualties.

The structure is Brazil's largest velodrome, built for the Rio 2016 Olympics, and now serves as a training facility for the national cycling and weightlifting teams. Inside the facility is the Olympic Museum, which exhibits artifacts and documents from the Games, including an Olympic torch and medals.

The velodrome's dome was constructed from synthetic canvas fabric. This lightweight membrane roof design is highly susceptible to rapid fire spread if ignited.

A section of the velodrome dome was charred after the fire. *Photo: Reuters*

Despite the damaged dome, the velodrome's structure and the museum below were largely unaffected. Mayor Eduardo Cavaliere cited preliminary assessments, stating the track remains intact, requiring only cleaning and maintenance.

The facility had previously caught fire twice in 2017 due to falling lights, though it sustained only minor damage.

Fire safety experts assert that this incident serves as a reminder that iconic structures require multi-layered fire prevention and suppression measures, extending beyond compliance with initial construction standards.

By Duc Trung (Based on reports from AP, Sun, Reuters)