The Houses of Parliament and Elizabeth Tower, commonly called Big Ben, are among London's most iconic landmarks and must-see London attractions. Technically, Big Ben is the name given to the massive bell inside the clock tower, which weighs more than 13 tons.  

The tower was designed by Augustus Pugin in a neo-gothic style. When completed in 1859, its clock was the largest and most accurate four-faced striking and chiming clock in the world. 

The tower stands 315 feet tall, and the climb from ground level to the belfry is 334 steps.  On 31 May 2009, celebrations were held to mark the tower's 150th anniversary.