1. This was the tallest buiding in the world from 1931 to 1967. What's it called?
2. This was the tallest building in the world from 1930 to 1931. What's it called?
3. These two buildings were, by some measures -- this stuff can get pretty arcane -- the first and second tallest buildings in the world from 1998 to 2004. What city are they in?
4. This building was, by some measures, the tallest in the world from 2004 to 2007. What city is it located in?
5. The building in the first picture, though still unfinished, is by most measures already the tallest in the world as of this posting. It is in a city that is also home to the extremely tall hotel shown in the second picture. What is that city?
Submit your answers in the comments.