House, the headquarters of MI5. However, the Grid, the base of operations of Section D, was a set constructed at the fifth floor in another building. Danny's apartment was also filmed in the same building. Another constructed set was the back of mobile surveillance vans, which was housed near the Grid set. Director Jonny Campbell helped search for several "interesting locations" for the first block to draw the audience with interesting visuals. This included a church in Smithfield and the Natural History Museum; in the latter's case, Campbell believed the location was "harking back" to traditional spy films. Filming there was expensive and management of the museum only allowed the crew to film for a few hours. The club Mace frequents was filmed at the Royal Automobile Club in Pall Mall. "The Sleeper" included scenes filmed at the University College London; a lecture room in the college was where the third series started filming. The explosion scene at the beginning of the episode was filmed at a council estate in Peckham. The estate was condemned for demolition, which proved to be a suitable location for a big explosion. The crew returned there again a month later to gather footage of the demolition work. Several exterior shots where Harry meets with government officials and his officers were filmed on walkways outside the Houses of Parliament. The upper-class home of Riff and B in "Celebrity" was filmed in a house in Kensington that was for sale for approximately £27 million at the time. Filming in public locations often took place on weekends, when they were closed off to the public. However, there were exceptions. Some scenes in "The Suffering of Strangers" were filmed outside the National Film Theatre in South Bank, a popular tourist destination. Shooting there became difficult as the crew had no control over the tourists. Other known London landmarks that were filmed at included Lord's Cricket Ground, St Martin-in-the-Fields, Tate Modern, the Old Bailey criminal court, Waterloo station, Empress State Building, and 30 St Mary Axe (the Gherkin). "Love and Death" was filmed in an actual Stena Line ferry that travelled from Harwich to the Hook of Holland, Netherlands; Stena allowed the producers to film in the ferry, though the cabins were filmed in a constructed studio set. The two actors present, Hawes and Oyelowo took precautions to avoid seasickness before boarding. After filming on board concluded, both actors