Where is the worlds fair hotel in Chicago?

The World's Fair Hotel cirrca 1890 was located at the intersection of 63rd & Wallace in Chicago. The Hotel was located at the SW corner. A United States Post Office now sits at that location. The hotel was built and operated by one of the United States first serial killers, H.H. Holmes.

The hotel no longer exists however, as it was burned to the ground by an unknown arsonist a few years after HH Holmes was executed by hanging for his crimes.