Answer: The $100 Bill

If you look at the back of most circulated U.S. bills, you’ll find a building of some note from the Washington D.C. area on most of them. The $5 bill has an engraving of the Lincoln Memorial (an unsurprising companion to Lincoln’s portrait on the front). The $10 bill has a portrait of Hamilton on the front and the U.S. Treasury Building on the back—fitting, as Hamilton was the first U.S. Secretary of the Treasury.

The $20 bill has Jackson on the front and the White House on the back—if you want a clear answer as to why, you’ll need to jump into a time machine and go back to 1928 when the current design was selected, as the reason is unknown even to historians at the U.S. Treasury. Like the $20 bill, the $50 bill features a former U.S. President (Grant) on the front and a landmark on the back (the U.S. Capitol building).

Outside of the bills that feature a Washington D.C. landmark—the $1 bill has the Great Seal of the United States on the back, the $2 bill has a portrait of the signing of the Declaration of Independence on the back, and then there is the $100 bill. Featuring Ben Franklin on the front, the back doesn’t have a U.S. capitol landmark, but instead an engraving of Independence Hall in Philadelphia where the Constitution of the United States was signed.