The costly renovation of the Seattle Space Needle officially began Thursday.

Crews will be onsite 24 hours a day, seven days a week.

Workers have already demolished and removed materials from the restaurant level. They’re also building and raising an elevated lift platform. It will be hoisted into place 500 feet in the air.

A gantry crane will be installed on the roof and at least 176 tons of glass will be added to the observation deck and at the restaurant level. Guests visiting the Needle will be able to see the work in progress.

The entire renovation project could take years and will cost approximately $100 million. However, the new restaurant and observation deck could be finished in less than a year.

It’s the largest investment into the landmark since its construction before the World’s Fair in 1962. The project is being funded by the Needle’s owner.

The restaurant will be closed from September to May 2018.

Space Needle CEO Ron Sevart previously told The Seattle Times in the past few years, visitors have noticed the drab interior of the 55-year-old structure and have said as much in a survey.