In the Knez Mihailova Street you will notice that fountain, made of beautiful white marble. In big European cities you will often find old fountains or modern, but simple ones. This one is somehow special, because it is modern, but very big, made of expensive material and also offers seatings around it. After a little research I found:
"Among the oldest drinking fountains there was also the Delijska drinking fountain, which was mentioned way back in the 17th century. On its place, already at the beginning of Knez Mihailova Street at the time, another drinking fountain was constructed in 1843, but its name remained the same. It was knocked down in 1889. When Knez Mihailova Street was reconstructed in 1987, another drinking fountain was constructed, which resembles the previous one."
Source and further information: www.beograd.rs/en/discover-belgrade/203207-famous-fountains/
And Wikipedia knows:
"Ruling prince of Serbia Alexander Karadordevic, built a drinking fountain (cesma), which became known as the Delijska fountain. It was demolished and built three times in the 19th century. The fourth reincarnation of the fountain, which stands today, was built in 1987 within the scopes of a major reconstruction of the street, which adapted it into the pedestrian zone. The present fountain is not on the same location as the old ones and is not identical in terms of architecture, but kept many elements from the old projects.
In 1987 there was a major reconstruction of Knez Mihailova and its transformation into the pedestrian zone. After six months of construction works, the street was open on 20 October 1987. It was paved with the black granite slabs from Jablanica, while a drinking fountain, made of white marble from Vencac, was erected in memory of former Delijska fountain which was further down the street."
Source and further information: en.wikipedia.org/wiki/Knez_Mihailova_Street