As most of us would likely guess, walking is the most popular physical activity in America. But people who walk for exercise do so at wildly varying speeds and intensities. Some stroll at a leisurely 2 miles per hour, which is low-intensity exercise. Others zip along at twice that pace or better, resulting in a sweatier workout.
Mummification is a process in which the skin and flesh of a corpse can be preserved. The process can occur either naturally, or it can be intentional. If it occurs naturally, it is the result of cold (as can be found in a glacier), acid (as can be found in a bog) or dryness.
Some people estimate 70 million mummies, but I think that's an underestimate. Mummification was carried out in Egypt, as I mentioned, for over 3,000 years. I'm sure more human mummies were made during this time period. If you look at animal mummies, several hundred thousand mummies have been found even in one cemetery. Countless mummies have been destroyed by tomb raiders seeking treasures within their linen wrappings.