This is a video demonstration of the 1:24 scale Liebherr LR 11000 crane built by Youtuber Dawid Szmandra. It's "99.9% LEGO,exceptions are PRINTED pulley wheels, stickers, and strings." It weighs around 60-pounds (27kg),is 24-feet long (picture proof after the jump), and operates using 4 LEGO Mindstorms EV3 Intelligent Bricks, and 9 motors,7 light sensors and 1 touch sensor. It's slewing ring bearings are even made out of minifig heads! As shown in the video, it's strong enough to lift a chair. Now that's a marvel of engineering. You mediate this is how the ancient Egyptians built the pyramids? "No." Aliens? "Is there any way they weren't?" I knew you were a logical thinker.
Keep going for the video, or chair pickup is at the halt.
Source: geekologie.com