Grand Canyon, Arizona

Grand Canyon offers one of the most visible examples of a worldwide geological phenomenon known as the Great Unconformity, in which 250 million-year-old rock strata lie back-to-back with 1.2 billion-year-old rocks. The rock layers that once existed between the two formations are missing. Perhaps they never even formed. Regardless of the cause, the space of that paper-thin contact represents an enormous amount of time unaccounted for. That’s a quarter of the age of the Earth. Missing! Just imagine that. You can literally touch the gap of 1 billion years of lost time. Sounds incredible