What the five biggest museums in the world?

What the five biggest museums in the world?
The 10 biggest museums in the world are:

1. The Smithsonian located in Washington D.C*
2. The Hermitage Museum located in St. Petersburg, Russia
3. The Met located in New York City**
4. The Grand Louvre located in Paris, France
5. The Deutsches Museum in Munich, Germany
6. The British Museum located in London, England
7. American Museum of Natural History located in New York City
8. The Museum Ludwig located in Cologne, Germany
9. Indore Central Museum in Indore, India
10. The Cairo Museum located in Egypt

Calculated by square footage.

*- Complex. Multiple locations.
**- One major location, one minor location (The Cloisters).