  Stephan's Quintet (SQ), discovered more than 100 years ago, is the most famous and well studied compact galaxy group. It has been observed in almost all wavebands, with the most advanced instruments including Spitzer, GALEX, HST, Chandra, VLA, and various large mm/submm telescopes/arrays such as the IRAM 30m and BIMA. The rich multi-band data reveal one of the most fascinating pictures in the universe, depicting a very complex web of interactions between member galaxies and various constituents of the intragroup medium (IGM), which in turn trigger some spectacular activities such as a 40 kpc large scale shock and a strong IGM starburst. In this talk I will give a review on these observations. 
Stephan's Quintet: A Multi-galaxy Collision