SETI focus - Megatelescopes

From historical to planet sized dark matter telescopes, this video will show you where the technology is going in humanities quest to understand universe. And find aliens, of course. I was not aware that there are telescopes with liquid mercury mirrors in operation. Maybe I will finally save up some money and buy a small refractor telescope or build a small Dobsonian.  

https://www.youtube.com/watch?v=ciECLSCgTKY

Source: Isaac Arthur