You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: SKYSCRAPERS 
Clue: After a construction boom fueled by oil & gas money, this capital city now has Europe's tallest building
moscow

Category: LANDMARKS 
Clue: In the 1879 Mathew Brady photo seen here, this structure was about 150 feet tall
washington monument

Category: SCIENTISTS 
Clue: When Einstein won the 1921 Nobel Prize in physics, he was a naturalized citizen of this country

switzerland