The South Pole Telescope (SPT) is a 10-metre (390 in) diameter telescope located at the Amundsen–Scott South Pole Station, Antarctica. The telescope is designed for observations in the microwave, millimeter-wave, and submillimeter-wave regions of the electromagnetic spectrum, with the particular design goal of measuring the faint, diffuse emission from the cosmic microwave background (CMB). Key results include the first detection of B-mode polarization in the CMB, the discovery of over 1000 clusters of galaxies using the Sunyaev–Zel'dovich effect, the discovery of a population of high-redshift, strongly lensed dusty galaxies, and unprecedentedly sensitive measurements of the primary temperature and polarization power spectra of the CMB at small angular scales.