Fancy riding in a hot air balloon? Now how about doing that underground? No? Well, that’s exactly what one Croatian man, Ivan Trifonov, has done and he also added a fifth Guinness World Record to his collection. The adventurous 70-year-old completed the underground hot air balloon ride in association with the Croatian tourism board. The event was completed at the Mamet Cave near the country’s west coast. “This was a once-in-a-lifetime opportunity for me to visit Tartarus (hell) right?” Trifonov said. “It has been an incredibly difficult project. You have to have the right balloon, the right weather, and the right support. I don’t believe this is going to be repeated by anyone ever again,” he added. Trifonov pictured flying into the cave.   Trifonov was the first man to try, and succeed at, this adventure. He flew into the cave, touching it’s bottom before flying out again. He had to use a specially-designed hot-air balloon for the feat which was smaller then normal. Trifonov has already hot air ballooned over the North Pole, the South Pole and the Mediterranean sea. He was also the first man to stand, dive and fly over the North Pole – all within 12 hours. https://www.youtube.com/watch?v=b0RtZL06EbI Video via YouTube/Croatia