70-year-old chemical engineer Ivan Trifonov has managed to successfully navigate a hot air balloon deep underground. The Bulgarian, who holds an Austrian passport, descended into the 675-feet deep Mamet Cave on Velebit Mountain, and returned up around 25 minutes later. Trifonov was perched in a small steel frame above twin gas tanks, instead of in a conventional basket. The stunt is believed to be a world’s first, and Trifonov is expected to send footage to the Guinness Book of World Records for it to be confirmed.
The keen pilot already hold four world records, including being the first to fly a hot air balloon over the Mediterranean Sea, over the North and South Poles, and the first to fly over Jerusalem, the Great Wall of China, and the Kremlin.
“It was very hard and I don’t think anyone else will ever repeat this venture,” Trifonov said.