Summertime is about relaxation, barbecues, and warm weather. 

And, apparently, UFOs.

In a series of memos dated all the way to the late 1940s, top CIA officials detail their mounting concern over extraterrestrial life descending upon us. One strange trend quickly emerged to those officials, and one that has remained constant in the 67 years since. Today, as they did in 1949, UFO sightings spike in the summer.

There are several theories about why this happens.

To read more, click here.