The world's biggest clean-up operations

As some of the world's biggest and most valuable landmarks, we knew it wouldn't be a quick spray and polish job but did you know it takes four weeks to clean The Shard, and that Big Ben's cleaners need to be particularly careful using only soap and water on the 312 pieces of opal glass that make up its clock face?

It's not just London's top attractions that get the VIP cleaning treatment either. Elsewhere, in Italy and India for example, the preening and polishing process is even more complex. The Colosseum's cleaners have been tackling the grime on the 1940-year-old amphitheatre with toothbrushes since the $25 million (£15.7 million) cleaning project began last year - its first full scrubdown in history - and are set to finish in 2016.

Staff at the Taj Mahal have other ideas when it comes to keeping the famous monument's marble looking shiny and white: they use mud clay and let it dry over the affected areas before removing it with soft brushes.

Music festivals, paintings and world-famous events also go through specialist cleaning similar to the world's architectural wonders.

Spain's La Tomatina festival gets so messy that fire engines are used to hose down the town of Bunol following the tomato-throwing tradition. And Glastonbury Festival requires a crew of 800 litter pickers over six weeks when the event ends.

Cleaning website Hassle.com has created an infographic of some of the world's biggest clean-ups. Take a look at the attractions and events that get the messiest.