Watching summer Barcelona sunset with a view of the whole city! (+ sightseeing & beach visit)

I've visited Barca couple of years ago so I've thought I've seen most of the important stuff. But this place we went to watch the sunset from was aaaaabsolutely amazing and definitely a must-do in Barca which I've skipped last time. It got a bit more crowded for my liking but I don't blame those people :) I'd be there every single day if I could :D