"?" (Serbian: Кафана „?” / Kafana „?”, Кафана „Знак питања” / Kafana ”Znak pitanja” or Кафана „Упитник” / Kafana „Upitnik”) is the oldest traditional tavern (kafana) situated in Belgrade, Serbia. Located at 6 Kralja Petra Street, the building is nearly 200 years old. The cuisine served is traditional, and specific starogradska music is played. "?" is one of the city's best known landmarks.
"?" was built in 1823 as a property of Miloš Obrenović I, Prince of Serbia, designed by an unnamed Greek architect. It was first used by that Macedonian diplomat and merchant, Naum Ičko, after which Prince Miloš gave it to his personal doctor Toma Kostić known as Ećim Toma for his efforts during the Second Serbian Uprising. Realizing its favourable location, Ećim Toma soon converted it into a kafana that was known around town as Ećim Toma's kafana. During the early 1830s the kafana was frequented by famous Serbian linguist and language reformer Vuk Stefanović Karadžić.
In 1878 its name was changed to Kod pastira (Shepherd's). It got its present unusual name in 1892, during a dispute with the Serbian Orthodox Church authorities over the owner's intention to change its name to Kod Saborne crkve (By the Saborna Church), to which the church authorities vehemently protested, not wanting to see a cathedral's name in the name of a kafana. So, as a temporary solution, the tavern's owner put a question mark on the door, and it soon became the official name of the place. For a while, out of respect for the church, smoking was prohibited inside the tavern, but this didn't last.
In the post-World War II period, the bistro was owned by Ivan Pavlović, but communist Yugoslav authorities nationalized the property in 1959. Sometime during the next thirty years it was declared a heritage spot and given landmark protection by the City of Belgrade's Landmark Office (Zavod za zaštitu spomenika grada Beograda).
Talk of privatizing the building first started in 2003. Then the tender auction of state-owned company UTP Varoš Kapija, which administered tavern "?" was scheduled for 25 November 2004. The starting value of the property was set at €2,500 per square meter, but ultimately the tender was canceled.
Strong resistance from the tavern's employees, from various public figures (mostly journalists who frequented the bistro), and from some civil groups, paid off in February 2007 when the Government of Serbia decided to exempt the restaurant from the privatization process and signed it over to city administration as a heritage spot. A petition, signed by 2,563 people, called for the privatization to be stopped.
The house was built in Balkan manner by “the Greek builders”. It was constructed in “bondruk” manner, with asymmetrically built interior and two bay windows on the main façade. It has a basement, ground floor and upper storey. It is situated toward the street and the lot depth occupies a garden and a yard. The basement was built from bricks and it has two massive vaults of 6x12m. The ground floor is arranged asymmetrically, consisting of three 4 x 9m, 2.5 x 4.5m and 7 x 7m chambers. The upper storey has six chambers: large 9 x 3m hall, two 5 x 5m symmetrically positioned rooms, forming bay windows over viewing the street, a 3.5 x 4m room and a 4 x 3m kitchen, with auxiliary room of 2.5 x 2.5m. Arrangement of rooms has remained unchanged despite of certain later partition works in the ground floor. 
At first, it was called “Kod Pastira“(“The Shepard’s”), then it was named “Kod Saborne Crkve” (“By the Cathedral Church”) in 1892 but not for long. This name was neither in compliance with the Decree about Taverns, nor with a position of church authorities, who found this to be insulting for the Church. The owner put out just a question mark "?" as a temporary solution and as sign of protest as well until dispute with authorities was resolved. This name remained to this day.
- (Inter)National restaurants — list of traditional restaurants by Tourist Organization of Belgrade
- "?" nije pod znakom pitanja — article on privatization of restaurant (Serbian)