1.21 Gigapops!

 is an Extreme track in Bloons TD 4 iOS. This track is harder than it looks since bloons will enter through all paths which are the lines. The entrances are also exits for the ones who enter in the other paths.

Trivia

 * This track is a reference to Back to the Future since the track appears to be a Flux capacitor. Also, the track's name comes from when Emmett Brown becomes shocked when the nuclear reaction should generate 1.21 gigawatts (See the video here).
 * 1.21 gigapops is equivalent to 1,210,000,000 pops.
 * Giga is alternative term for the Bilion or 10⁹.