The new Lego Tower will have the world’s tallest building in the US and the world first concrete building, with the completion of the site expected later this year.
Construction began in May this year on the former Army base on the US-Mexico border, and the structure was expected to be completed in 2019.
The US Department of Homeland Security (DHS) awarded the project a $3.5 billion contract in April, with construction to begin in 2020.
The site is located on the Arizona border, a US territory and an important entry point into the US for many travellers, including the world-famous theme park Tomorrowland.
The new building is designed to hold up to 600,000 people, according to the Associated Press news agency, which said it was also expected to host an outdoor market.
The building is part of a planned expansion of the Tomorrowland theme park, which opened in the 1970s.
The structure will be one of the tallest structures on the west coast of the US, with its base expected to rise as high as 14 stories, according the Associated Post news agency.