Diving into an ancient salt mine

The world's first dive inside a salt mine

This is Rhiannan Iffland and Constantin Popovici

they jumped over 390 ft into Salina Turda

one of the world’s oldest salt mines

Location: Turda, Romania

(SOUNDBITE) (English) CONSTANTIN POPOVICI SAYING:

"The big challenge I would say it's the salinity. It's super salty compared to a normal ocean which makes it more tough on your body on the impact. Also being in a cave it's totally dark, we have lights but it's still not a natural perfect condition to dive so that's another challenging thing."

The water and air temperatures were just 12°C/53.6°F

But the true challenge was the speedy deceleration

from over 50 mph to zero in twice the usual speed

(SOUNDBITE) (English) RHIANNAN IFFLAND SAYING:

"It feels strange hitting the water and also to see Costa hit the water and it looks like a perfect entry, it was still clean but the salt water just wants to make its way up and do a bubble."