The world's largest scientific instrument is under construction beneath the polar ice

Encompassing a square kilometer of the Antarctic icecap, the IceCube array of photodetectors is designed to spot neutrinos, those most elusive of particles. You can see pictures of IceCube being built at the South Pole, or a video (quicktime) of what the detector network looks like. Other massive neutrino detectors are also photogenic, like the Super Kamiokande (other pictures), located in a mine a kilometer underground, or BooNe at Fermilab, filled with 800 tons of mineral oil.