Tucked away to the rear of St. Mark's Orthodox Church in Belgrade is the Zasto? (Why?) Memorial, which commemorates those who lost their lives when a Serbian television station was the target of a missile.

On the evening of 23rd April 1999, the North Atlantic Treaty Organization (NATO) bombed the Radio Television of Serbia (RTS) headquarters in Belgrade. The incident occurred during a bombing campaign against the Federal Republic of Yugoslavia. After a single NATO missile hit the building, 16 RTS employees were killed. Most of the victims were technicians, security workers, or makeup artists.  Many of the employees were trapped in the rubble of the ruined building for days, only able to communicate with those outside via phone. Somehow, RTS managed to return to the air in less than 24 hours, airing from a different, secret location.

At the time, NATO justified the bombing stating that it was intended to disrupt the communications network of the Yugoslav Armed Forces, which was committing a genocide against the Albanian population of Kosovo. NATO also accused RTS of spreading propaganda against the Albanians. But the Yugoslav government stated the RTS building served no military purpose and should not have been a military target. Human Rights Watch also condemned the attack, suggesting that a better target could have been RTS transmitters rather than the studio itself.

Over the years, there have been plans to restore the building, but as yet it still stands as a ruined reminder of NATO's bombing campaign in Belgrade.