For most of the last 157 years, the great bell known as Big Ben has sounded the hour in London, its reassuring and sonorous gong pealing out over the Thames, part of the sonic landscape of the city. But early next year, for the third time in living memory, Big Ben will fall silent – a silence so notable that some Londoners may even find it deafening. It is time, in the words of the Shawn Colvin song, for a few small repairs. Well, not so small, actually. They will come to an estimated £29 million, or more than $42 million – and will take three years. Big Ben will be silent for “several months,” the team performing the repairs says. The great bell is housed in the 315-foot-tall Elizabeth Tower, at the north end of the Houses of Parliament. But cracks have developed in the tower’s masonry and the belfry is corroding. It needs work. And so does the Great Clock. After more than a century and a half of nearly unbroken service, there are fears that – horrors! – the clock could become inaccurate, or even stop altogether. So a variety of problems will be addressed. The clock be serviced, the pendulum examined. The bearings holding the hands onto the dial will be attended to. The tower will be restored. An elevator will be installed to help the handicapped and to facilitate the evacuation of anyone who gets hurt. And, for those who find climbing the 334 stone steps a time-consuming business, the tower will now feature, for the first time, a toilet.