What you see above is 32 minutes of something going wrong during each launch. While humanity has been launching things into space since the 1950s, you can see just how hard it is — over and over again. And when humans are riding aboard the rockets, the toll becomes more tragic.
According to the YouTube author of the video above, the vehicles shown include “V2, Vanguard TV3, Explorer S-1, Redstone 1, Titan I, Titan II, Titan IV, Atlas, Atlas-Centaur, N1, Delta, Delta III, Foton, Soyuz, Long March, Zenith, Space Shuttle Challenger, and more.”
Naturally, with each failure the engineers examine the systems and work to fix things for next time. A famous example is the Challenger shuttle explosion, which you can see about halfway through the video. There were multiple causes for the failure (human and technical), but one of them was an O-ring that failed in cold weather before the launch. NASA revised the launch rules and with contractors, made some changes to the booster rocket design, as a 2010 Air and Space Smithsonian article points out:
Freezing temperatures weakened an O-ring seal in a joint between two segments of the right booster. The weakness allowed hot gases to burn through the casing, causing the shuttle to break apart on ascent, which killed the seven-member crew. Two joints were redesigned with interlocking walls that had new bolts, pins, sensors, seals, and a third O-ring.
Still, launching is a risky business. That’s why it’s so important that engineers try to catch problems before they happen, and that as soon as a problem is seen, it’s fixed.