The Atlanta Falcons NFL American football franchise has moved a step closer to completing the construction of its new Mercedes-Benz Stadium after the roof successfully closed for the first time.

The 70,000-capacity venue, which has been dogged by cost overruns and delays, is due to open in time for the team’s 2017 pre-season game on August 26.

Falcons chief executive Steve Cannon tweeted two photos of the roof before and after it closed for the first time.

Below are the pictures showing the open and closed roof:

According to the Falcons Wire website, it takes between seven and 12 minutes for the roof, which slides closed like a camera lens, to close once the process has begun.

The retractable roof is made from eight different 500-tonne pieces that slot into place.

In front of the Mercedes-Benz Stadium, there will also an enormous metallic sculpture of a Falcon, made from 33 tonnes of stainless steel.

Late last year, the project had budgeted no more than $12.8m (€12.3m/£10.4m) to build a pedestrian bridge.

However, Reed and Public Works Commissioner Richard Mendoza signed off on a contract, seen by the Atlanta Journal-Constitution, that estimates the final cost at $23.2m, 81 per cent more than the original budget.

The stadium will also serve as the home of Major League Soccer franchise Atlanta United.

Image: Michael Barera