Starting in late August, one of London’s largest—and noisiest—national symbols will go silent: As BBC News reports, Big Ben (which has rung on the hour for 157 years) will cease chiming until 2021. The measure is intended to protect workers completing restoration work on both the clock and its surrounding structure.

Big Ben will still chime on New Year’s Eve, Remembrance Sunday (a UK holiday that honors veterans), and other special occasions, but its last hourly bong will sound on Monday, August 21. Meanwhile, scaffolding has already been erected around the clock tower, and repairs have begun.

The clock tower last received extensive conservation work in the early 1980s. Officials say that the clock’s hands, pendulum, and inner workings all have problems “which need to be dealt with immediately to ensure that the clock can continue to work properly,” according to Parliament’s official website.

“Surveys are still being carried out to identify the extent of the works required to the tower itself, but we have already identified areas of concern, including cracks in masonry, leaks, erosion, and severe rusting of metalwork,” officials added. “There is a risk that if not addressed as a matter of urgency, the clock may fail or [structural] problems may become acute.”

Big Ben’s clock will be dismantled piece by piece, so its four dials can be cleaned and fixed. Its faces will be temporarily covered, but an electric motor will continue to drive the clock hands so it can keep telling time. Architects also plan to modernize the clock tower by making it more energy-efficient, and adding an elevator, toilet, and kitchen.

"This essential program of works will safeguard the clock on a long-term basis, as well as protecting and preserving its home—the Elizabeth Tower," the clock's keeper Steve Jaggs told the BBC.

For the uninitiated, the name “Big Ben” is often used to describe the tower, the clock, and the bell, but it originally described the largest of the clock’s five bells, which stands more than 7 feet tall and weighs more than 14 tons. As for the clock’s surrounding tower, it was dubbed Elizabeth Tower in 2012, to celebrate Queen Elizabeth II’s 60-year reign.