The Louvre Museum in Paris shut down following a theft on Sunday morning, thwarting visits by large numbers of tourists from around the world.
Police continue to hunt for the perpetrators of what appears to be an organized crime.
The French government says more than one thief broke into the museum at around 9:30 a.m. on Sunday, local time, and stole precious jewels on display.
The museum had already opened its doors to the public. No injuries have been reported.
Local media report that nine pieces of jewelry were stolen, including a tiara and necklace of Napoleon the Third's wife. One piece of jewelry -- a diamond and emerald crown -- was found outside the museum. It was reportedly damaged.
The thieves are believed to have broken in through an upstairs window by using a freight lift and escaped on scooters.
Interior Minister Laurent Nunez said the robbery took only seven minutes.
Prosecutors in Paris say they are investigating four people on suspicion of involvement in the heist.
People left the area around the Louvre after the announcement it would be closed for the rest of the day.
A Japanese woman on a honeymoon said she was surprised to see police officers at the museum and learned of the robbery on the internet. She added she wants to come back before she leaves the city in a few days.

Quiz 1:
Q: Where did the theft occur that caused the closure of the Louvre Museum?
A. New York City
B. Paris
C. London
D. Rome

[Answer block]
Answers: Quiz 1: B

Quiz 2:
Q: Approximately how long did the robbery at the Louvre Museum take?
A. 3 hours
B. 7 minutes
C. 9 hours
D. 1 day

[Answer block]
Answers: Quiz 2: B

Quiz 3:
Q: What was one of the items stolen during the robbery at the Louvre Museum?
A. Napoleon the Third's tiara and necklace
B. A diamond and emerald crown (found outside the museum)
C. Leonardo da Vinci's Mona Lisa
D. The Venus de Milo statue

[Answer block]
Answers: Quiz 3: A