What's Mir?

Basically, Mir is like... this old space station

Building the ISS

Building the ISS took a looooooong time: it's still not finished! The last few elements should arrive in 2019. To build it, NASA used it's Space Shuttle(well, until they stopped using it), first launching the core then other elements. Here is a video about the ISS's assembly

Additional Links For A Better Comprehension

ISS Walkthrough: An Interactive 3D Simulation Of The International Space Station
ISS Low-Res 3D Model