As London's famous clock tower gets a face-lift, here are a few facts surrounding the chimes of Big Ben.

WHAT'S IN A NAME?

Big Ben is the name commonly used for the Great Bell in the Elizabeth Tower, which is attached to the Palace of Westminster , the U.K. parliament in London on the north bank of the River Thames. It's thought to be named after Sir Benjamin Hall , the First Commissioner for Works while the bell was being cast and tested.

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HOW BIG IS BEN?

Big Ben weighs 13.5 British tons (15.1 U.S. tons) — about the size of two large African Elephants. It is 2.2 meters (7 feet, 2 ½ inches) high and has a diameter of 2.7 meters (8 feet, 10 inches).

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WHAT TIME IS IT?

The tower was completed in 1859 and Big Ben's first peals rang out over London on July 11 that year. Big Ben has rung out hourly through the reigns of six British monarchs.

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BEN'S GRANDFATHER CLOCK

The first recorded clock tower on the site was erected over 700 years ago. According to records at the Palace of Westminster, a clock tower was built in New Palace Yard around 1289. It had one dial and one bell.

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BREAKING NEWS

A few months into its first year, Big Ben was found to be fractured in two places. While a solution was being sought, one of the smaller bells in the tower was used to strike the hour — but its tone was quieter and not as distinctive. Three years later, the problem was solved after a suggestion from the Astronomer Royal, Sir George Airy . Big Ben was turned and its hammer size reduced, allowing it to be used again.

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BIG SISTER IS WATCHING

At the top of the Elizabeth Tower is a lantern known as the Ayrton Light, which is illuminated whenever the House of Commons or the House of Lords is in session. Palace historians believe it was installed so Queen Victoria (1837-1901) could gaze out from Buckingham Palace and see if lawmakers were working.

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STRIKING THE RIGHT NOTE

Musicians may be interested to know that when it is struck, Big Ben chimes out the note "E." The four smaller bells in the tower, which are rung on the 'quarter' hours, strike "G sharp," ''F sharp," ''E" and "B."

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HIGH NOON

If visitors want to cast their eyes on Big Ben, they have to climb 334 stone steps — and any evacuations in the event of an accident are carried out using a complex abseiling rig. A renovation now taking place will make room for an elevator. The Big Ben and the Elizabeth Tower tours are only available to UK residents.

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BEN TRAVELS AT THE SPEED OF LIGHT

If a person stands at the bottom of Big Ben's tower with a portable radio and listens to the chimes live on radio, they will hear the peals on the radio first before hearing them from the tower.

Why? Radio waves travel at 186,000 miles per second (the speed of light), as does the signal from the Big Ben microphone to the radio station. Sound itself travels a measly 0.2 miles per second.