: The number of sites vying for the Cherenkov Telescope Array
(CTA), a next-generation ground-based gamma-ray observatory, is slowly being whittled down. The telescope will comprise two arrays of instruments: a 19-dish array in the Northern Hemisphere and a 99-dish array in the Southern Hemisphere. On 10 April the 12 CTA partner countries met in Munich and narrowed the site list down to two potential locations in the Southern Hemisphere and four in the Northern. Factors being considered include weather, earthquake risk, political stability, and financial contributions of host nations. Once it is up and running around 2020, the CTA will focus on the center of the Milky Way, where it will look for gamma rays, dark matter, and supermassive black holes.