There are two famous museums called "National Gallery" that you might be interested in:
The National Gallery in London: This is the more famous one, founded in 1824 and located in Trafalgar Square. It houses a vast collection of over 2,300 paintings from the 13th to the 19th centuries, including works by European masters like Van Gogh, da Vinci, and Michelangelo. Entry to the main collection is free! National Gallery, London
The National Gallery of Art in Washington D.C.: This museum is located on the National Mall and has collections spanning from the medieval era to the modern day, though with a stronger focus on American and European art
