Hunkered down in their hives and drunk on smoke, Notre Dame's smallest official residents — some 180,000 bees — somehow managed to survive the inferno that consumed the cathedral's ancient wooden roof.
Confounding officials who thought they had perished, the bees clung to life, protecting their queen.
"It's a big day. I am so relieved. I saw satellite photos that showed the three hives didn't burn," Notre Dame beekeeper Nicolas Geant told The Associated Press on Friday.
"Instead of killing them, the CO2 (from smoke) makes them drunk, puts them to sleep," he explained.
Geant has overseen the bees since 2013, when three hives were installed on the roof of the stone sacristy that joins the south end of the monument. The move was part of a Paris-wide initiative to boost declining bee numbers. Hives were also introduced above Paris' gilded Opera.
The cathedral's hives were lower than Notre Dame's main roof and the 19th-century spire that burned and collapsed during Monday evening's fire.
Since bees don't have lungs, they can't die from smoke inhalation — but they can die from excessive heat. European bees, unlike some bee species elsewhere, don't abandon their hives when facing danger.
"When bees sense fire, they gorge themselves on honey and stay to protect their queen, who doesn't move," Geant said. "I saw how big the flames were, so I immediately thought it was going to kill the bees. Even though they were 30 meters (nearly 100 feet) lower than the top roof, the wax in the hives melts at 63 degrees Celsius (145.4 Fahrenheit)."
If the wax that protects their hive melts, the bees simply die inside, Geant explained.
Smoke, on the other hand, is innocuous. Beekeepers regularly smoke out the hives to sedate the colony whenever they need access inside. The hives produce around 75 kilograms (165 pounds) of honey annually, which is sold to Notre Dame employees.
Notre Dame officials saw the bees on top of the sacristy Friday, buzzing in and out of their hives.
"I wouldn't call it a miracle, but I'm very, very happy," Geant added.