Wing Chun (or Wing Tsun) is a more modern version of Kung Fu. There are various stories to how it was developed. It's principle of simultaneous attack and defend is what is included in the Krav Maga system. It's known for being Bruce Lee's first martial art and the basis for his Jeet Kune Do system (so it gets an extra cool bonus point for that). Power generation and speed in this style is fascinating. The stance is a little awkward and cannot be applied when under pressure in real combat, but the basic structure and movements like bridging along with reaction training drills are very effective.
Relationship to Krav Maga
As mentioned, the principle of simultaneous attack and defend is the same as what Krav Maga uses."Block + Strike" is twice as fast as "Block & Strike". The reaction training and flinch response drills work well for self defence and the knowledge of close combat fighting, which is more realistic than the fast majority of traditional Martial Arts.