I once read that the leaders/royalty of each country were actually related to each other. What happened to these families after world war 1. Were these families still in power in WWII? Are they still around today?
Yes they were...to a certain extent. Not all the Royal families were related but most were.
King George V of Great Britain, Kaiser Wilhelm II of Germany and Tsar Nicholas II of Russia were all cousins. They were related through the common ancestor of Queen Victoria of Great Britain. Victoria had five children: Edward, Victoria, Alice, Alfred and Beatrice. Edward married Alexandra of Denmark who was the sister of Dagmar of Denmark (also known as Maria Feodorovna). Dagmar married Alexander III of Russia. Together they had six children, the eldest of which was Nicholas, who would succeed his father and become Tsar of Russia with the title Tsar Nicholas II. Now because Edward VII, Queen Victoria's eldest son, was Nicholas' uncle, that made Edward's son, George (the future King George V), his cousin. Queen Victoria's first daughter, also called Victoria. Princess Victoria would marry the German Emperor Frederick III and would have a son, Wilhelm II, the future Kaiser of Germany during the First World War.
Combined with the descendants of Christian IX of Denmark, Victoria's and Christian's grandchildren would occupy the thrones of Great Britain, Germany, Russia, Norway, Denmark, Greece, Spain and Romania at the outbreak of the First World War. It is little wonder that Victoria is know as the grandmother of Europe and Christian as the Father-in-Law of Europe.
After the First World War, things changed dramatically. Kaiser Wilhelm II abdicated in 1918, going into exile in the Netherlands until his death. Germany became a republic after his abdication. In Russia, Tsar Nicholas II abdicated both for himself and his son in 1917 following the February Revolution. The throne passed to his brother, Grand Duke Michael, who refused it. After the October Revolution, Nicholas and his family passed into the hands of the Bolsheviks who imprisoned them and at the end of April 1918, the family was transported to Yekaterinburg where they were all executed by gunshot in July 1918.
The descendants of Queen Victoria and Christian IX still occupy the thrones of Denmark, the United Kingdom, Norway and Spain as well as a few others through marriage since the end of the First World War.
Thank you for this response. It was really helpful. Do any of these royal family's still hold any power or are the just rich familys with no significance nowadays.