There are many mysterious phenomena and locations on the planet, from haunted castles to flames that rise out of stone to what appears to be a waterfall of blood – and although some have reasonable explanations, they still incite myths, rumors, and folk legends. 

24/7 Tempo has compiled a list of 45 of the most mysterious places on earth by reviewing dozens of travel sites and encyclopedic sources for information on natural wonders and man-made marvels that have mythical origins or offer unexplained experiences. Every continent is represented, as are some of the most remote islands in the world. (These are the most colorful natural wonders on earth.)

Some of the most mysterious places on earth are man-made, including secret military bases, haunted mansions, and eccentric architectural constructions. Others are natural wonders, including colorful acid lakes, deep underwater sinkholes, and strange rock formations. (There are many amazing sites in our own country. Here are stunning photos of America’s largest attractions.)

Click here to see the most mysterious places on Earth

A few of these places are the sites of mysterious disappearances while others harbor gravity-defying optical illusions. Local legends of hauntings, extra-terrestrials, and mythical creatures still surround some of these sites, many of which have become popular tourist attractions, drawing visitors with their perplexing or unsettling qualities.