At the Sherlock Holmes Museum, you can find a reproduction of Sherlock Holmes' famous home office. Take a photo of you sitting in Sherlock Holmes' armchair or just look at Sherlock's stuff which is placed in the room exactly the way it is described in Doyle's stories. Additionally, on the upper floors you can find Dr Watson's bedroom with his personal belongings as well as wax figures which show scenes from the Sherlock Holmes stories.
According to Sir Arthur Conan Doyle, Sherlock Holmes and his friend Dr Watson lived from 1881 to 1904 in this house, whose house number is 221B. But that is obviously wrong because in Victorian times, the house numbers in Baker Street only went up until 100. Therefore, Sherlock Holmes, whether he is fictional or real, cannot have lived at 221B Baker Street. Later on, this house number has been created to host the Sherlock Holmes Museum. Image source
The Sherlock Holmes Museum, whose admission fee is £15 for adults and £10 for children (that are defined as people under 16 years), is located near Marylebone and Baker Street Station. If you would like more information about the museum, click here to visit its web page.