There were more than 110 scientific talks, of which 27 are plenary; among the participants are researchers and young scientists, as well as students from universities in Russia and abroad (Belarus, India, Serbia, Uzbekistan, Tajikistan, Algeria, Iraq, Pakistan, Ecuador, Palestine, Colombia, Mexico, UAE). The series of conferences "OTHA" began in 2011. Over the past 15 years, more than 1,500 participants have presented reports, of which about 260 - with plenary reports; the geography of the participants covered more than 52 countries; 13 special issues have been published in leading international publications. Full information about the events can be found on the OTHA website: https://otha.sfedu.ru/start/ .