One of the big selling points of drones is that they can get to areas that aren't exactly safe or accessible by humans. That's why watching quadrocopters assembling a rope bridge that's sturdy enough for a person to walk across is so damned awesome -- it immediately calls to mind a real-world use scenario that probably all of us can relate to. The video below was filmed at RTH Zurich Flying Machine Arena in Switzerland, and, according to the YouTube description, aside from the scaffolding on either side of the bridge, the structure is "entirely realized by flying machines." Every knot and braid in the 7.4 meter (just over 24 feet) bridge was tied by the UAVs using Dyneema rope. As Robohub tells it, the material has a low weight-to-strength ratio that makes it pretty great for aerial construction uses.
That isn't the whole story, though. Before the first ropes are wrapped, the room in question is outfitted with motion capture devices that offer positional measurements that feed back into the custom-made drones. The researchers involved say that this experiment "acts as a demonstrator" and is the first effort showing that diminutive air-borne drones are able to build load-bearing structures at full scale. No, you can't drive a tank over this, but the bridge is definitely more useful than drone-delivered mistletoe.