Looking through a collection of historical images at reddit, this one jumped out from the list (which is heavy on World War II photos). These are the nine monarchs of Europe who attended the funeral of the United Kingdom’s King Edward VII on May 20, 1910. They are:
Standing, from left to right: King Haakon VII of Norway, Tsar Ferdinand of Bulgaria, King Manuel II of Portugal, Kaiser Wilhelm II of the German Empire, King George I of Greece and King Albert I of Belgium. Seated, from left to right: King Alfonso XIII of Spain, King-Emperor George V of the United Kingdom and King Frederick VIII of Denmark.
They were all related to Edward VII; George V was his son and the rest were in-laws or cousins. The funeral was also attended by scores of queens, princes, princesses, and other royalty. U.S. president Theodore Roosevelt was there representing the United States. See the photo full-size.
“Three Rings for the Elven-kings under the sky,
Seven for the Dwarf-lords in halls of stone,
NINE FOR MORAL MEN, DOOMED TO DIE,
One for the Dark Lord on his dark throne
In the Land of Mordor where the Shadows lie.
One Ring to rule them all, One Ring to find them,
One Ring to bring them all and in the darkness bind them.
In the Land of Mordor where the Shadows lie.”