The Pentagon is the headquarters building of the United States Department of Defense. It's one of the world's largest office buildings and recognizable (from above) by it's five-sided concentric rings.
Please make sure you read your reservation's cancellation policy!
You'll be given this information with the available room rates after you select a hotel and specify dates. Many hotels have cancellation penalties associated with their best rates. Most offer "Book Now and Pay Later" options that are less restrictive, but slightly more expensive.