Paper sky lanterns may have started the fire that burned down the Krefeld Zoo's Ape House.

Burning Monkey House in Krefeld zoo
Firemen work at the burning monkey house of the zoo in Krefeld, western Germany, on early January 1, 2020.

Dozens of animals including monkeys, apes, and birds were burned to death at a German zoo after a devastating fire broke out in the Ape House on New Year’s Eve.

Shortly after midnight, police and firefighters responded to a call that the Ape House had burnt down to “the basic scaffolding,” the zoo’s Facebook page reported Tuesday. Over 30 animals were killed in the terrible incident, including several monkeys, five orangutans, two gorillas, fruit bats, and birds, according to CBS News.

Burned Monkey House in Krefeld Zoo
Credit: David Young/Getty

Two chimpanzees — Bally and Limbo — survived the fire and sustained only minor injuries. The pair is currently being housed in the Gorilla Garden where they are receiving care from zoo veterinarians, the zoo’s website reported. This area, located near the Ape House, did not catch on fire.

“It’s close to a miracle that Bally, a 40-year-old female chimpanzee, and Limbo, a younger male, survived this inferno,” Wolfgang Dressen, the zoo director, told CBS News.

He added that the event was “an unfathomable tragedy,” one which the zoo will have to “seriously work through the mourning process.”

The blaze may have started due to fire-lit paper lanterns which were launched into the sky on New Year’s Eve, police told CBS News.

“People reported seeing those sky lanterns flying at low altitude near the zoo and then it started burning,” Gerd Hoppman, a Krefeld police officer, said.

He noted, however, that these laterns are illegal in Krefeld as well as in many other areas of Germany.

Representatives for the Krefeld Zoo did not immediately respond to People’s request for comment.

Memorial for burned animals
Flowers, candles, stuffed animals and placards are placed at a makeshift memorial for the animals that died in a fire at the zoo's monkey house on January 1, 2020 at the main entrance of the zoo in Krefeld, western Germany

As the zoo begins to recover from the horrrifying experience, they are responding to the “overwhelming wave of compassion and assistance” and hope that the public will continue to donate to help keep the apes safe in the future.

The zoo is set to reopen Thursday with construction of a new Ape House to follow.

This Story Originally Appeared On People