About 100 firefighters responded to a scene that had, police noted, “massive amounts of water” pour into the street. Videos posted to social media from guests inside the hotel show significant damage and cascades of water all over — except in the empty tank. Shards of glass, mangled lamps, bellhop trolleys and tables are shown littered throughout the lobby.

When Berlin Mayor Franziska Giffey arrived to assess what Berlin police described as “unbelievable maritime damage,” she expressed relief that no one was seriously injured. About 300 guests and employees were safely evacuated from the building, authorities said.

“Despite all the destruction, we were still very lucky,” Giffey said, according to the Associated Press. The mayor added that “we would have had terrible human damage” had the aquarium burst even an hour later on Friday.

The cause of the aquarium explosion remains unclear and is under investigation, the fire service said. Police told reporters that there is no evidence that the incident was a planned attack. Berlin is experiencing freezing temperatures that got down to as low as 14 degrees Fahrenheit overnight.

At 82 feet tall, AquaDom was lauded by its creators as the biggest free-standing cylindrical tank in the world. The tank, which was built in the hotel in 2003 and last modernized in 2020, featured a 10-minute elevator ride that allowed guests to admire the fish up close. More than 80 types of fish lived inside the aquarium, including blue tang and clownfish popularized by the animated movie “Finding Nemo.”

“Unfortunately, none of the 1,500 fish could be saved,” Giffey told reporters.

Almut Neumann, a municipal official in charge of environmental issues for Berlin’s Mitte district, told the German news agency dpa that efforts were underway to save hundreds of additional smaller fish in aquariums beneath the hotel lobby that were in danger of not receiving the oxygen needed to survive.

“Now it’s about evacuating them quickly,” Neumann said.

Sandra Weeser, a member of the federal parliament who was staying at the hotel, said in an interview on local television that dying fish had poured onto the street.

“It’s a picture of devastation with lots of dead fish and broken shards,” she said. “The ones that might have been saved were frozen to death.”

Sea Life, the operator of AquaDom, noted on its website that a separate aquarium inside the hotel was closed after the explosion.

“We ask for your understanding and will announce as soon as we are open again,” the company wrote.

In addition to the aquarium, a Lindt chocolate store, several restaurants and an underground parking garage next to the hotel were damaged, according to authorities. Officials added that safety experts are inspecting whether the hotel faced structural damage.

Two hotel guests, Karin Wicki and Sandra Hoffmann, recounted how the Radisson is now unrecognizable after the aquarium burst.

“Everything is destroyed inside,” the guests told dpa. “There are dead fish. All the furniture is destroyed. The windows are destroyed. Shards everywhere.”

Radisson guests documented the scene early Friday. Some guests noted that they woke up due to what they described as “a rumbling beneath us.”

“The tank in our hotel … blew?” one guest tweeted alongside a photo of the destruction. One guest added that she “was admiring the fish and divers just last night!”

Another tweeted a video of the chaos and was left wondering what he was witnessing.

“The fish tank of my hotel just exploded in the middle of the night,” one guest said. “WHAT’S GOING ON.”