Dubna is the science-city of nuclear physicists known thanks to its Hadron Collider and Dubnii,105th chemical element in the periodic table. The city has strong ski and water-ski traditions, Waterski World Cup and World Cup was organized in Dubna. The cross-country skiing marathon Nikolov Perervoz has been held since 1995. Start of the marathon is given at the mouth of the river near the site where in 1134 the wooden fortress Dubna was built by order of Yuri Dolgoruky. 400 participants from 80 cities of Russia traditionally starts in Nikolov Perevoz.