The monument honouring the 52 dead in the attack on London's transport system in 2005 cost nearly £1 million and has 52 stainless steel columns, 11.5ft tall.
It was unveiled in 2009 at a memorial attended by the Prince of Wales, the then Prime Minister Gordon Brown and other political leaders.
The columns are grouped together in four clusters, reflecting the separate locations of the bombings - Tavistock Square, Edgware Road, King's Cross and Aldgate.
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Police were called to Kilburn High Road at 5.20pm after reports of a shooting.
In just 24 hours the offer was retweeted more than a thousand times on Twitter.
What a year it's been full of ups and down, turmoil and change and it seems events here in London have got the entire nation talking.