The Institut de radioastronomie millimétrique (IRAM) operates two observatories for radio astronomy at millimeter wavelengths, which are open to the international astronomical community: the 30 m single-dish radio telescope located on Pico Veleta (2850 m) in the Spanish Sierra Nevada (Andalucia, Spain), and the six-antenna Plateau de Bure Interferometer (2550 m) in the French Alps. Both sites are at high altitude to reduce the absorption by water vapor. The observatories are supported by the IRAM offices and laboratories in Granada and Grenoble, respectively.