A new concourse at London's King's Cross station - a key transport hub for the Olympics - has been unveiled.
The multi-million pound facility will more than double capacity at the central London station, which is used by 47 million passengers every year.
Thousands of extra people are expected to travel through the hub this summer as it provides a vital link to the Olympic Park in Stratford, east London.
The concourse, part of a wider revamp, is enclosed by a steel web-like roof.
Transport secretary Justine Greening, Mayor of London Boris Johnson and Network Rail chief executive David Higgins attended a ceremony on Wednesday evening to mark the project's completion.
The doors will be opened to the public on Monday.
The Victorian Grade I listed station, which opened in 1852, is undergoing a £550m redevelopment.
This project, overseen by architects John McAslan and Partners, includes the new western concourse, refurbishing the main train shed and the Great Northern Hotel, a new public square and transforming station buildings into offices.
Work to complete the concourse was prioritised so it would be finished in time to accommodate the millions of sports fans who will flock to London for the Olympics.
Typically, London's transport network sees 25 million journeys a day and three million more are expected on the busiest day of the Games.
Transport for London has warned that during the Games the morning peak periods will be particularly busy at King's Cross St Pancras Tube station.
Monday 30 July has been identified as being likely to be the busiest while predictions show 31 July and 2, 3 and 7 August will also be exceptionally busy.
It is hoped a combination of improved signage, flow and more escalators on the huge concourse will work to minimise congestion at King's Cross station.
The facility also offers improved links with the Tube and St Pancras International station where high-speed Javelin trains will take spectators non-stop to Stratford in seven minutes.
Due to the unusual shape of the concourse, the structure incorporates an arrangement of beams radiating out across the roof and a diagrid system.
This is supported by 16 concrete columns and one central funnel column which leads the eye to the original booking hall which has been reinstated as a ticketing area - complete with original proportions and features.
Harry Potter films
Work has also been undertaken to refurbish the main train shed roof and platforms, construct a new platform, a footbridge and subway.
The two wrought iron and timber barrel-vaulted roofs of the main train shed are currently being refurbished using a sophisticated "roller-coaster" system.
A canopy which is moved along on rails has been used to create a construction site above the railway, which allows the work to continue while the station is fully operational.
In some areas up to 17 layers of paint have been stripped off to reveal the original framework.
The station's 118-year-old wrought-iron Handyside Bridge, which featured in the Harry Potter films, has been removed because of requirements for disabled passengers and the anticipated increase in passenger numbers.
It has been replaced with a contemporary glass and steel bridge providing access to all platforms, via lift and escalator, as well as linking the main train shed with the mezzanine of the new concourse.
But during Games-time all work will be suspended to minimise disruption for travellers.
Once the Games are over, the old concourse, a temporary building built on the site in 1972 and which has its planning permission renewed every four years, will be ripped down to provide the site for the city's newest square.
Forming the final part of the project, and due for completion in autumn 2013, it will reveal the station's original façade for the first time in 150 years.