Watch Russian freediving champion Natalia Molchanova is feared dead after going missing on Sunday.
The 53-year-old was diving for fun off Formentera, a Spanish island near Ibiza, when she failed to surface.
Search efforts have been continuing but it is feared she may have been caught up in strong underwater currents.
Her passion for freediving - diving while holding one's breath -'burned so deep inside of her that she dedicated her life to it', her family said.
She was a competitive swimmer as a young woman but left the sport to have a family, going on to take up freediving some 20 years later.
She became 'the most decorated competitive freediver in the world', with 41 world records, said her family and the global freediving federation AIDA in a joint statement..