The plain, black door with the number 10 is deceptively nondescript. Aside from the unusual placement of the doorknob in the center of the door, it looks not much different than any of the countless front doors to residences throughout the world. Appearances can be deceiving. Some of the world’s most powerful people walk through its doorway. If the door could talk, it would tell endless tales of its unique witness to history.

We speak of the door at 10 Downing Street, London, England. It is the residence of the Prime Minister of the United Kingdom. Today, we open the door and explore the fun and fascinating history behind one of the world’s most famous addresses.

Downing Street bears the name of Sir George Downing (1624-1684). This rather unpleasant character assumed so many different roles during his lifetime that it is doubtful that even he knew who he really was. At various times he was a preacher, soldier, diplomat, spy, and politician. His political loyalties bounced back and forth during the time of the overthrow of Charles I, the government of Oliver Cromwell, and the restoration of the monarchy under Charles II.

Downing made his fortune in real estate speculation. In 1654, he acquired the property to the south of St. James’s Park and planned to build a row of terraced townhouses “for persons of good quality to inhabit in….” The street on which those houses were built was named Downing Street. The largest of the houses was assigned the address Number 5. In 1779, it was renumbered as Number 10.

The homes may have been intended for persons of good quality, but the same could not be said of the quality of the structure. Almost three hundred years later, Winston Churchill wrote that Number 10 was, “Shaky and lightly built by the profiteering contractor whose name they bear.”

Number 10 remained as private property for nearly 80 years. The last private resident of the address moved out in the early 1730s. Details about that last private resident have been lost to history, aside from the fact that his name was “Mr. Chicken.”

Number 10 entered into government service when George II offered it to Sir Robert Walpole. Walpole was the First Lord of the Treasury and is viewed as the first Prime Minister. The king intended the house to be a gift, but Walpole declined to accept it in his personal capacity. Instead, he asked the king to declare it as the official residence of the First Lord of the Treasury. To this day 10 Downing Street is the official residence of the First Lord of the Treasury, not the Prime Minister, although since 1905 these have always been the same person. The brass letterbox on the door continues to have that title engraved on it.

Walpole oversaw the refurbishing of the new official residence. He connected it with an adjoining house and placed the official entrance facing Downing Street. He used the ground floor for business and resided with his family upstairs.

It was in the 1770s that Number 10 obtained the first edition of the iconic door with which the address is identified. Under the orders of Chancellor of the Exchequer Charles Townshend and by the design of architect Kenton Couse, the six-paneled, black oak Georgian style door took shape. It featured a center doorknob, lion knocker, and the brass mail slot with “First Lord of the Treasury” engraved thereon.

There was a brief period when the entrance to Number 10 looked noticeably different than it does today. In 1908, Prime Minister Henry Asquith, had the door changed from black to dark green. It was said that his wife, Emma Alice Margaret Asquith, was the primary influencer of this change. The green door did not last long, however. No sooner did the Asquith Administration end in 1916 than the familiar black returned to the entrance of the residence.

The exterior of the building is just as black as the door. Originally, the color was yellow, however. In the 1950s, Number 10 underwent extensive repairs and renovation due to the massive damage caused by German bombing raids during World War II. At that time, it was discovered that the familiar black of the bricks was the result of pollution, rather than paint. The original yellow of the bricks had long been obscured by London’s famous smog. Despite that revelation, black has remained as the preferred appearance, although its current shade is due to paint, not grime.

The Asquith years aside, the appearance of the door has remained essentially unchanged for over 200 years. Its design and function have evolved, however. Today, the doorknob is purely decorative. The door cannot be opened from the outside. Instead, a security guard stationed inside continually monitors outside activity and decides who shall be granted access to the interior.

The need to enhance security was made clear in 1991 when the IRA targeted Number 10 in a mortar attack. The wood door was replaced with a reinforced steel replica. The original can be found at the Churchill Museum.

Number 10 is not only home to the Prime Minister but also to one of the staff members. That staff member does not receive an official government salary but is provided free room and board. He is a tabby cat by the name of Larry, and he has served as Chief Mouser to the Cabinet Office since 2011.

Larry was recruited from Battersea Dogs & Cats Home on the recommendation for his mousing skills. He is the latest in a distinguished line of felines at Number 10. Munich Mouser had a cat’s-eye view of history while serving under Neville Chamberlain and Winston Churchill. The longest-serving feline-in-residence, Wilberforce, controlled the mouse population at the historic residence for 18 years, from 1970 to 1988.

Seeing Number 10 for yourself is going to be difficult, at least if you want to do so in person. Most of Downing Street is blocked off by an imposing iron gate. Aside from becoming Prime Minister, serving in high government, or wrangling an invitation to visit, your best bet to see Number 10 up close is going to be a virtual tour. You can do this and explore Number 10’s most famous rooms and learn more about its history at the Google Cultural Institute.