Here's a bit of Halley that most people (even those who come here) never see. It's the magnetometer shaft. On the outside it looks like a big wooden box on the snow:
But inside it leads to a tunnel about 7m under the snow (and getting deeper) that contains a very sensitive magnetometer.
And the small lab where the computers for the magnetometers are:
The magnetometers are very sensitive and need to be thermally and physically stable which is why they are in a tunnel down in the snow. They are used to measure electrical currents flowing in the ionosphere which tells scientists about the way that solar wind connects to the earths atmosphere.