The Bulgarians tried to gain independence from the Ottoman Empire, and a key component in that was the Bulgarian National Revival, and in 1876 the Bulgarians had an uprising in the month of April, but the Ottomans were too strong so it was unsuccessful. This triggered Russia to intervene, since it had a big interest in the Balkans, so that prompted another war between the Russians and the Ottomans, with the Russians winning and Bulgaria managing to get its independence in 1878.
Under orders from President Wilson, U.S. Brigadier General John J. Pershing launched a punitive expedition into Mexico to capture or kill Villa and disperse his rebels.