London ? London landmark Big Ben fell silent Saturday to undergo 32 hours of essential maintenance – its longest shutdown in 22 years.

The clock, in the tower of Westminster Palace – London’s Houses of Parliament, stopped after 8 a.m. local time Saturday, and is not expected to be back in action until 4 p.m. today.

Specialist engineers are examining the clock while workers from the Whitechapel Bell Foundry will be replacing the rubber hammer buffers on three of the four quarter bells, the Westminster chimes, and on Big Ben, the 13-ton bell which tolls the hour.

After the buffers are replaced, the bells must be re-tuned, which takes several hours.