More than 1,000 people are expected at the annual ceremony at the Russian Chapel in the northwest of the country. The landmark was built by the surviving prisoners of war 102 years ago. The ceremony will be addressed by President Borut Pahor. The some 20km long Vršič mountain pass was built to provide a support link for Austrian troops fighting in the Soča valley. It is estimated that at least 10,000 Russian prisoners of war lost their lives building the mountain pass.