Almost the last word.

The article discusses the question of when in Earth's history it would be possible to comfortably survive if one were to invent a time machine. The answer depends on the definition of "comfortably survive." If it means breathing air, drinking water, and avoiding extreme temperatures, then the Ediacaran Period, around 640-540 million years ago, might be suitable. However, if it means finding food and avoiding predators, then the Holocene Epoch, starting around 11,700 years ago, would be more appropriate. The article also mentions the risks of altering history and encountering hostile civilizations. Another question addressed in the article is how Roman road builders knew which way to go. They used beacons and a surveying instrument called a groma to establish straight routes. The article explains that Roman roads were not always perfectly straight and often followed pre-existing trackways. The Romans adopted the existing landscape and developed it with their innovations. [Extracted from the article]