His vision was that there should be a view of each building from the other, but this was quickly forgotten. As early as the mid-19th century, a new Treasury was constructed, to replace the previous one that had burnt down. This was built so that it stuck out into the road, and now blocks the view of the Capitol from the White House; it has since become a national monument in its own right.
How the Avenue got its name is still debated. Many of Washington's avenues are named after the nation's states; it is likely that conferring Pennsylvania upon the district's most important street was a gesture to the city of Philadelphia, stripped of its status as America's capital city when Washington took over in 1800.
L'Enfant's plan was that this grand avenue should be the home of institutions and seats of learning, but although this may once have been the case, modern Pennsylvania Avenue has no shortage of shops and restaurants. And many of the Avenue's best-known buildings have been hotels. One of the most famous is the Willard, once the National, whose proximity to the White House has made it a favourite residence of statesmen and politicians for almost two centuries.
This beaux arts-style building has often been at the centre of events. After the Civil War, President Grant used to go to the Willard to smoke a cigar in the hotel lobby during the afternoon, and those who came to try to have a word with him became known as "lobbyists". The "Star-Spangled Banner" was sung there for the first time in 1814; the "Battle Hymn of the Republic" was written there in 1862; and in 1963, Martin Luther King was staying at the Willard when he wrote his "I have a dream" speech.