One of the buildings here in Toledo, when I worked for a radio shop. I was checking an antenna. I was about 35 stories up. I was on the Sears Tower observation deck, but that is not all the way to the top.
Blackpool Tower is about the only structure I've been up, which others might consider a tall building. The UK doesn't have that many tall buildings in comparison to other countries.
Yes, that is subjective, but I believe the Burj Khalifa is the tallest building in the world, so if someone has been to the top of that building, it would dwarf all others.