No, not a student residence. Nor the place that your golf balls disappear when you make a bad drive. It is an analog of a black hole, made from light. I quote: “pulses of light travelling down an optical fibre can be made to affect other light waves in much the same way as a black hole does.” Apparently these things even have their own version of Hawking radiation.

Nature has a lot more on this piece of physics fabulousness.