Sentence:  Upon arriving at Baltimore , Selkirk on December 22 wrote to John Quincy Adams , Secretary of State at <WSD>Washington</WSD> , inquiring about laws covering trade with `` Missouri and Illinois Territories '' . 
Meaning of the word marked with <WSD> tags:  the capital of the United States in the District of Columbia and a tourist mecca; George Washington commissioned Charles L'Enfant to lay out the city in 1791