The book is dedicated to a number of mysteries of domestic and world history of the 20th century. Sometimes it seems that this century, which has only recently sunk into oblivion, gives us more reasons for thought and material for research than all the past centuries and millennia of human history. Two world wars, many local military conflicts, revolutions and civil wars, conspiracies, putschs and coups, economic “miracles” and severe crises, outstanding cultural achievements and great scientific discoveries, the ups and downs of the human spirit - all this fit into a relatively short chronological period . The reader is offered original versions, the results of research by scientists, local historians, and journalists. The authors of the presented materials restore the “true history of Sacco and Vanzetti,” trace the fates of Grand Duchess Anastasia and Martin Bormann, analyze information about the deaths of Kolchak and Chapaev, Vasily Stalin and John Kennedy, about the treasures of Baron Ungern and the Amber Room, talk about the expeditions that went in search of the mysterious lands of the Russian North, and about UFO accidents, about the disasters of the Titanic and the Empress Maria.