Where there are tall buildings there are also tall elevators. Saudi Arabia’s Kingdom Tower, designed by Chicago-based Adrian Smith + Gordon Gill Architecture, will be the tallest building in the world if constructed as planned. The building is expected to stand 3,281 feet tall and will require elevators the likes of which the world has never seen. Luckily for the Kingdom Tower, one elevator company is researching the extremes of vertical circulation.

The Finnish elevator company KONE has already begun construction of prototype elevators for the project, but these test lifts don’t jut up into the sky. They drop deep beneath the earth’s surface. They company is currently testing and constructing their technologically advanced elevators in an abandoned 19th century mine shaft in South Finland.

Since the site was chosen in 2008 as an ideal elevator testing ground, KONE has made progress in developing Ultrarope, a new piece of technology that will allow elevators to travel distances up to 1,000 meters: an unimaginable feat until now. Unlike most modern elevators which typically use steel cables, Ultrarope houses a carbon fiber core surrounded by a high-friction coat. The carbon fiber core is very light, reduces energy consumption noticeably, and decreases the weight of nearly all the major components operating the elevator. In addition to the markedly reduced energy consumption, this new cable material will last twice as long as regular steel lines and does not require frequent lubrication for maintenance.

The Kingdom Tower will be filled with 65 elevators and escalators, each designed to maximize comfort and speed while also ensuring the safety of its occupants. KONE was previously tasked with designing the elevators for the third tallest building in the world, the Makkah Clock Royal Tower in Saudi Arabia.