Baby bears are born in the winter and stay inside their dens until spring. Every time a cub finishes nursing, the mom licks its bottom to make it urinate. The mother bear then drinks the urine, which helps keep the den clean.

Quasars emit more energy than 100 giant galaxies.

The Hoover Dam was built to last 2,000 years. Its concrete will not be fully cured for another 500 years.

AMAZING FACTS