Number 11 (Story #1), December 3, 1990 by Phillip F. Schewe and Ben Stein HERA, THE ELECTRON-PROTON COLLIDER in Hamburg, Germany, is now built and will undergo tests. The only machine of its type in the world, HERA (Hadron Elektron Ring Anlage) will send beams of 30-GeV electrons against beams of 820-GeV protons. The electron-proton collisions, which will be observed in two large detectors, called ZEUS and H1, will, like the much lower-energy fixed-target collisions that won Henry Kendall, Jerome Friedman, and Richard Taylor a Nobel Prize in October, probe the inner structure of the proton. (Nature, November 22, 1990.)