This X-ray image was produced by combining a dozen Chandra observations made of the central region of the Milky Way. The colors represent low (red), medium (green) and high (blue) energy X-rays. Chandra’s unique resolving power has allowed astronomers to identify thousands of point-like X-ray sources due to neutron stars, black holes, white dwarfs, foreground stars, and background galaxies. What remains is a diffuse X-ray glow extending from the upper left to the lower right, along the direction of the disk of the Galaxy. The Chandra data indicate that the diffuse glow is a mixture of 10-million-degree Celsius gas and 100-million-degree gas. Shock waves from supernova explosions are the most likely explanation for heating the 10-million degree gas, but how the 100-million-degree gas is heated is a mystery.