We live in a world of constant monitoring. It may be difficult to believe, but the average person in a large American city is caught on camera about 70 times a day. From the closed circuit eyes at workplaces and educational institutions to the discreet lenses mounted at gas stations and hidden in ATM machines, we are seen and recorded wherever we go. Add to this the smartphone in your pocket, various social media accounts, the whole nine yards of Internet surfing patterns-and a reasonably accurate picture of your activities emerges-information which can be readily pulled from the ether of floating data points by law enforcement agencies, private eyes, and employers. It may seem a tad naive to talk, in such a The Man is watching you scenario, of mysterious disappearances. This is as far as the argument goes though. There are more than 2000 reports of missing persons every day in the United States alone. That mind-boggling number translates to nearly 900,000 lost people in a year. It seems human beings are notoriously prone to being lost, and unlike misplaced car keys found under sofa cushions or in the dogs water bowl, we can be much harder to find, in many cases, impossible to find. Individuals aside, even ships, aircraft, and whole colonies of folks have absented themselves from civilization, never to be seen or heard from again. The list of 10 inexplicable disappearances here includes some famous missing cases, some which garnered media attention from the word go, some that resulted in long-drawn but ultimately fruitless investigations and then inevitably, the ones which are bizarre enough to warrant the involvement of those lovable conspiracy theory characters; the aliens. These were some cases of famous disappearances in history. People go missing all the time, many are kidnapped or stranded, and others disappear voluntarily to start new lives. Many are found through clever detective work and public help. Others, like the ones in this list, walk into the twilight zone...never to return.