Watch this crazy video of Russian daredevils climbing the world's second tallest building

This photo taken on Aug. 4, 2013, shows a bird's eye view of the partially constructed Shanghai Tower. The 2,073-foot-high skyscraper is due to be completed later this year.

Warning: The following video is terrifying.

Russian adrenaline junkies Vitaliy Raskalov, 20, and Vadim Makhorov, 24, have filmed themselves conquering another super-tall structure, this time the 2,073-foot-high Shanghai Tower.

The masked daredevil duo, armed with head-mounted GoPro cameras and nerves of steel, completed their stomach-turning climb to the top of the world's second tallest building after the Burj Khalifa in Dubai in just two hours. 

But sneaking onto the construction site during the Chinese New Year holiday and reaching the top of the skyscraper while escaping detection by security guards was not enough for the thrill-seeking pair.

They climbed the crane that was at the top of the building without the aid of ropes or harnesses.

The footage and photos shot by the Russian adventurers are breathtaking, but also a little sickening. 

The vertigo-inducing video has gone viral since it was posted on YouTube earlier on Thursday, receiving nearly 2.5 million views as of this writing.

Makhorov of Moscow told The Telegraph that the pair began their ascent at night when there were fewer security guards patrolling the construction site.

"It took about two hours to get to the top, but when we got there we could only see clouds,” Makhorov said.

"We had to wait for hours for the clouds to part, but it was well worth the wait, the view was like something from an aircraft window.

"We were not afraid at all and we have never had any injuries as a result of our sky walking.

"Our target was to climb the highest tower in China and the seconds highest in the world, it felt amazing to accomplish it, the sky is the limit!"

Raskalov and Makhorov have scaled structures around the world, including Barcelona's Sagrada Familia, Cologne's Cathedral, and the Eiffel Tower and Notre Dame in Paris.

Click here to watch videos of some of their other exploits. 

"We are just chasing the dream and always looking to go to the next highest point to see the things no one else gets to see," Raskalov told the Daily Mail last year.

"We don't mean to trespass or harm anyone one so we do often have to wait until the coast is clear."

"But when you get there the views are spectacular and we want to keep going until we have mastered every city."