While it seems incredible that a passenger jet could go missing, that’s exactly what happened in 2014.

This lavishly decorated chamber of the Catherine Palace in Tsarskoye Selo (now Pushkin), Russia, was dismantled and looted by Nazi soldiers, and its whereabouts are unknown.

For more than a century, researchers and scholars have attempted to decipher this illustrated manuscript.

After hijacking a plane in 1971, he parachuted out of the aircraft with the ransom money and disappeared.

The identity of the man who brutally killed at least five women in 1888 has obsessed detectives and armchair sleuths for decades.

While that’s one hypothesis, we don’t really know. The cause of his death is one of literature’s great unsolved mysteries—fitting for the man who created the genre of detective fiction.

In 1908 there was an enormous explosion in Siberia, Russia, estimated to have been equivalent to the explosive force of as much as 15 megatons of TNT.