Only one-fifth of air is oxygen. Most of the rest is nitrogen.

Mount Everest is more than 29-thousand feet high, which makes it almost
50-percent taller than Mount McKinley.

Mount McKinley is taller than Africa's Kilimanjaro or Japan's Mount Fuji
or any of the Alps. That should give you an idea how tall Everest really is.

Over 90% of the calories you burn are used to maintain your body
temperature. A good way to lose weight is, therefore, to expose your
body to the cold.

The insulation of the fuel tanks on a Saturn V rocket was so good an ice
cube placed inside would take 8 years to melt.

Mosquito repellents don't repel. They hide you. The spray blocks the
mosquito's sensors so they don't know you are there.