The US military science agency DARPA has issued an appeal asking for help in finding a new, specific test site for her. This is a structure that can be described as an "underground labyrinth", an abandoned subway or a closed shopping center. Particular emphasis is placed on the artificial origin of the object, the natural caves of DARPA are not of interest.
The agency's tweets show eloquent examples: an abandoned train station, empty stations, old bunkers, underground parking lots. But the ruins will not work, you need a place where you can move freely in different directions, where there is a real risk of getting lost. Ideally, this is a kind of closed object, isolated from the outside world, with the ability to organize experiments there without the risk of colliding with random people. An underground location is not necessary, the main thing is that it is impossible to navigate from the inside by the sun, stars and other signs that are relevant in open space.
And we need such an unusual DARPA training ground for the SubT Challenge program. It is devoted to technologies of orientation in space, mapping and movement through tunnels and underground structures. Military goals are secondary, in the first place is the development of methods for organizing various work in an unknown confined space. For example, rescuing people from rubble after earthquakes or surviving in tunnels in case of surface contamination.
Urban buildings have their own characteristics, which is why DARPA needs a human-made object. Previously, for the SubT Challenge, work has already been carried out in old mines in Colorado and Pittsburgh, and now the researchers want to move to an urban environment.