No. 10 Downing Street is the official residence of the British Prime Minister, unlike Buckingham Palace, where there are conditions for public visits, it is heavily guarded. At No. 1 Downing Street at Whitehall Crossing, there is an iron fence that blocks visitors. Inside the fence, several policemen with guns are guarding. The real building No. 10 Downing Street is invisible. There are many Chinese tourists here. Many people take photos with the police across the iron fence. The police are very friendly.