Conversation so far:
what style of architecture is the lincoln memorial
The Lincoln Memorial is a Greek Revival style structure built in 1922.
what is the purpose of the lincoln memorial
The Lincoln Memorial is an American national memorial built to honor the 16th President of the United States, Abraham Lincoln.
who was the architect of the lincoln memorial
The architect of the Lincoln Memorial was Henry Bacon.
what is the shape of the lincoln memorial
The Lincoln Memorial building is in the form of a Greek Doric temple.

Question: when was the memorial built
Self-contained rewrite: when was the lincoln memorial built