It seems like a country just can't get world power status until they have an embassy overrun by locals in Tehran.
The United States Embassy in Iran was infamously overrun in 1979, with American hostages being held for 444 days. The last U.S. Ambassador to Iran, William H. Sullivan, was not among those hostages, and fortunately none of the American embassy workers were killed.
Probably less well-known is when the citizens of Tehran overran the Russian embassy in 1829. At the time, Iran was known as Persia and the two countries just concluded a two-year border war — which did not go well for the Persians.
Persia, especially the capital, was full of anti-Russian sentiment. The Persians had been forced to give up much of their northern border areas, lost access to the Caspian Sea, and most importantly (for these events) liberated any Armenian held captive to move to Russian territory.
The first official postwar Russian envoy to Persia was the renowned Russian comedy writer Alexander Griboyedov. The playwright and author recently married into Russian aristocracy, which resulted in his Persian posting.
Shortly after the Tsar sent Griboyedov to Tehran as Minister Plenipotentiary (a rank just below an official ambassador), two Christian Armenian women and one Armenian eunuch escaped from the Persian royal family harem, seeking refuge in the Russian embassy.
The Shah demanded their return, but Griboyedov wouldn't give in. The terms of a treaty gave the Armenians the right to return to Russia. Thousands of angry Persians turned out to protest the Russian embassy, but Griboyedov wouldn't budge.
The National Interest cited "contemporary accounts" in the telling of this story, saying the locals were incited by mullahs to storm the building. The Minister Plenipotentiary, other Russian diplomats, and the embassy guards in the building tried to fight as best they could but were overwhelmed.
Their bodies were dragged into the streets of Tehran, each decapitated in turn.
Griboyedov's body was eventually returned to his native Tbilisi, now in Georgia. Shah Fath-Ali sent an envoy to Tsar Nicholas I of Russia as an apology for Griboyedov's death, along with an 88-carat diamond, known as the Shah Diamond, in the hopes the Tsar wouldn't return with the Russian army.
The diamond is still on display in the Kremlin, a grim reminder of how even the most powerful nations can still be victims of a mob.