STAVROPOL, Russia (Reuters) - President Vladimir Putin may be criticized by the West for the annexation of Crimea from Ukraine in 2014, but at home his public approval ratings have been boosted. The operation to seize the peninsula, hailed by Russian nationalists as  The Crimean Spring , led to an upsurge in what is called  military and patriotic education  of Russian youths. In the southern region of Stavropol, interest has been revived in the Cossacks, a warrior class in tsarist times, and in the history of tsarist and modern wars which Moscow fought in the North Caucasus region. The Cossacks, who were portrayed as peaceful ploughmen in quiet times, were swift to repel attacks from nearby regions, such as Chechnya and Dagestan, or join Moscow s military campaigns elsewhere.  Tomorrow begins today,  reads the motto of a cadet school in Stavropol that was named after Alexei Yermolov, a 19th century Russian general who conquered the Caucasus for the Russian empire. A Reuters photo essay (reut.rs/2jp4dgu) captures images from the General Yermolov Cadet School training in Stavropol and in the countryside. Most cadets come from families of active Russian soldiers or officers from other security forces. About 40 percent of school leavers join the military or law enforcement agencies. Many instructors spent years in  hot spots  or conflict zones. A group of teenagers from the  Patriot  club in Crimea visited the school s field camp, named  Russian Knights , over the summer. Up to 600 boys and girls train there each summer. This camp trains more than 1,500 teenagers a year. Physical exercises go hand-in-hand with weapons training, marksmanship tests, car driving and even parachuting. 