The state of Colorado is the latest location to experience the baffling 'mystery boom' phenomenon that is seemingly occurring more frequently than ever.
Residents in a number of Colorado cities and towns were rocked on Monday evening when they heard a pair of loud, unexplained sounds that many witnesses likened to that of an explosion.
As often happens with similar incidents involving the enigmatic and maddening booms, attempts by local media to solve the case have proven to be fruitless.
Both the USGS and an area Air Force base could provide no explanation for the sound which has also stumped meteorologists and other experts.
The circumstances surrounding the Colorado boom closely mirror those of other strange sounds which have been with increasing in frequency in recent years and particularly over the course of 2017.
Find out about what has been a proverbial 'boom' in mystery sound cases this year at the Coast to Coast AM website.