What, in your opinion, is the most significant or impressive invention/innovation in the crypto space so far?

I’ve only been in crypto for about a year, but it’s mind blowing to me how quick the speed of change and growth is in cryptocurrency. I’m trying to think of technological historical parallels to crypto and all I can think about at the moment is the Internet itself.

Curious to hear your opinions. Obviously the creation of crypto itself springs to mind but let’s put that aside. It’s probably not the most significant, but for me the use of Layer 2 scaling solutions is really impressive. As an ETH holder I’m a biased but for me this is a game changer and will be instrumental - at least in the short term - in keeping Ethereum above the others (apart from Bitcoin, of course).

What do you guys think?