Washington D.C. welcomes approximately 15 million domestic visitors each year, and 1.5 million are international visitors.  (Washington D.C. Tourism Board) There are more than 100 restaurants in the downtown Washington DC area alone with Travel & Leisure calling it "one of the most exciting restaurant cities of the East Coast." The Washington Nationals Ball Park is the first green-certified ballpark in the United States.   DC is also the first major city to require developers to adhere to guidelines established by the U.S. Green Building Council.