World-renowned free diver Natalia Molchanova is feared dead after a recreational dive in Spain.

According to The New York Times, Molchanova disappeared after a routine dive near the Spanish island of Formentera. The 53-year-old Russian never resurfaced after diving into the Balearic Sea. A massive search for Molchanova was underway to find the free diver but has been unsuccessful so far. The 23-time world champion is feared dead.

According to Bleacher Report, Molchanova holds an incredible 41 free diving world records. Kimmo Lahtinen, president of the global free diving governing body AIDA, has given her condolences to the family of Molchanova.

"She was a freediving superstar, and we all thought nothing could harm her," he said. "Nothing could happen to her, but, you know, we are playing with the ocean, and when you play with the ocean, you know who is the strongest one."

She isn't the only one to offer condolences. William Trubridge, a 15-time world record holder in free diving, tweeted the following:

According to CNN, Molchanova once held her breath for nine minutes and dived at a depth of 101 meters using only a fin.

In a joint statement with the Molchanova family and AIDA, they said, "Natalia Molchanova was recreationally freediving off the coast of Spain on Aug. 2, 2015 when she was separated from her peers. She was diving without fins to around 30-40 meters (98-132 feet) and (supposedly) got into (a) strong underwater current."

The search continues with the use of an underwater robot capable of expanding the search 500 meters deep into the ocean.

Molchanova would be survived by her son Alexey. Check out a video of her breaking a world record below: