Sunburn can occur in less than 15 minutes, and in seconds when exposed to non-shielded welding arcs or other sources of intense ultraviolet light. Nevertheless, the inflicted harm is often not immediately obvious. After the exposure, skin may turn red in as little as 30 minutes but most often takes 2 to 6 hours.
A caboose is a manned North American rail transport vehicle coupled at the end of a freight train. Cabooses provided shelter for crew at the end of a train, who were required for switching and shunting, and to keep a lookout for load shifting, damage to equipment and cargo, or overheating axles (hot boxes).
The Panama Canal is not the only water line connecting the Atlantic and Pacific Oceans. There’s a place in Wyoming—deep in the Teton Wilderness Area of the Bridger-Teton National Forest—in which a creek splits in two. Like the canal, this creek connects the two oceans dividing North America in two parts.