Cast your mind back to the 2012 Olympic and Paralympic games in London and you'll probably recall the glorious feats of athleticism, a national sense of unity derived from shared patriotism and unforgettable ceremonies to mark the open and close of the games. What we don't often mention whilst looking back at one the the capital's greatest modern triumphs are the numerous state-of-the-art buildings and facilities we erected in the name of sport for the 17 days of the Olympics and the 12 days of the Paralympics.
Those with particularly strong memories may even remember the bid that helped clinch the games, rife with promises that the Olympics would transform a neglected area of London and bring an end to British underachievement in sport.
Four years down the line, we take a look at what those billion pound buildings are used for now.
Then: This was where we saw Mo Farah smash it in the 10,000 metres and Jessica Ennis seal heptathlon gold. For each and every one of the spectators packed into the stadium, it was magical. So what happened when the passion and ebullience of the games vanished from the stadium?
Now: For a long time after the end of the games, the stadium was left dormant as Leyton Orient and West Ham football clubs, Intelligent Transport Services, Formula One and University College of Football Business launched bids to take over the stadium. Victors West Ham will play their first match on the new turf in July.
The conversion of the stadium from an athletics centre into a football ground has been long and tiresome, and much controversy has surrounded who is funding the transformation and how its upkeep will be paid for.
As well as its regular tenants, the stadium was also used for a number of matches in the 2015 Rugby World Cup, and is due to host the 2017 IAAF World Championships in Athletics and the 2017 IPC Athletics World Championships.
Then: The brand spanking new studio, one, two, three and four bed apartments were home to around 17,000 of the world's finest athletes during the games. The village covered 27 hectares of land and contained 67 different buildings, each with good access to recreation spaces, parks, shops and cafes. The legacy promised 2,818 news homes for Londoners, 1,000 of which would be three or four bedroom family homes and 1,379 of which were purchased by the Triathlon Homes consortium for affordable housing after 2012.
Now: East Village's 2,818 homes are split across two landlords - 51% Get Living London (market rent) and 49% Triathlon Homes (affordable homes).
Living like an Olympian doesn't come in cheap for those paying market rent - a one bedroom apartment will set you back £395 a week, while a two bed townhouse can set you back £460. The village's homes currently on the market can be found here, if you're feeling rich (or curious).
Then: A giant red tower designed by Anish Kapoor functioning both as a piece of public art and a viewing tower. A cool £16 million of funding for the tower came from Britain's richest man, steel tycoon Lakshmi Mittal.
Now: The structure has been modified to incorporate the world's tallest tunnel slide, designed by Carsten Holler, an idea floated by the London Legal Development Corporation as a way to get more visitors up the tower. Tickets were originally to cost £5, but are currently £15 for adults and £10 for children.
You can also abseil down the tower for £85 per person, descending 80 metres from the upper observation platform to the ground. In case you were wondering what that looks like, two of those irksome YouTube celebrities did it on camera last year.
Then: The magnificent centre where Tom Daley dove his way to a bronze medal for team GB, while Rebecca Adlington thrashed her way to a bronze in women's 800m freestyle. Designed by the Pritzker Prize-winning architect Zaha Hadid, the magnificent Stadium boasts a 50m competition pool, a 25m diving pool and a 50m warm-up pool, and originally was fitted with "wings" to hold a capacity of 17,500 visitors.
Now: Several modifications have been made, including taking off the "wings" to make the capacity just 2,500, with another 1,000 available for major events. Day-to-day, it's now a council run leisure centre, allowing adults to take a dip like an Olympian from just £4.95 and kids from £2.50.
Then: This space hosted handball and fencing events, as well as goalball during the Paralympics in front of crowds of up to 7,500. Many enthused that the Box That Rocks could become a venue for sport and music as well as being open for daily use by locals, with the Olympic Park Legacy Committee estimating that it would attract 650,000 visitors a year.
Now: The arena was home to the British Basketball League team London Lions for a season and is now used for community events like Better's summer holiday activity camps, as well as food and comedy festivals and various other sporting events, which are listed here. Members of the Better gym can also book the Copper Box for events, with prices starting at £93.01.
Location: Waltham Forest
Then: This venue held training pools for swimmers, synchronised swimmers and water polo players during the 2012 Olympics, before hosting wheelchair tennis to crowds of 10,500 during the Paralympics.
Now: Now the Lee Valley Tennis and Hockey Centre, equipped with four indoor and six outdoor tennis courts and five-a-side football pitches. The space has hosted a bunch of other sporting events, most notably the 2015 EuroHockey Nations Championships.
London Olympics Media Centre
Then: The massive 24 hour media hub catered to some 20,000 broadcasters, journalists and photographers all bringing updates across the country and around the world. It included a whole catering village plus a multi-story car park to accommodate for its various occupants and visitors.
Now: Now renamed Here East the lease to this centre is split between the Mayor's Olympic legacy agency and iCITY, a consortium of Infinity and property developers Delancey, which owns half the Olympic village. Plans are still in motion to turn this site into a centre for London's "digital quarter".
BT Sport has been broadcasting from the centre for several years, while Loughborough University and Hackney Community College also have access to the centre's facilities.