In pretty much every conceivable way, Dubai’s Burj Khalifa defies the imagination.

At 2,722 feet it is far and away the tallest building in the world, it required $1.5 billion, five years, and thousands of skilled workers to build, and now it also boasts the world’s largest LED screen.

Although construction on the Burj Khalifa finished in 2010, construction of the massive LED screen that now serves as its outer façade didn’t begin until 2014. Work on the massive 33,000-square foot screen wrapped up last year, but getting to that point wasn’t easy.

“One of the challenges we had was limited access points to reach the exterior of the façade, so we had to open some portions,” explains Bashar Kassab, Burj Khalifa’s director of technical services, in the above video.

As shown in the video, the portions of the façade opened up by the Burj’s technical services team were pretty small, often requiring engineers to crawl through openings in windows before suspending themselves thousands of feet above Dubai with the dozens of miles of cables required by the project.

Watching the engineers install the LED paneling is not for the faint of heart, but according to one engineer, the conditions shown in the video were pretty good. More info