Forests have become wastelands. Can they return to wilderness?
With the Washington Monument reopening, take a look at what was once called the tallest.
For more than 3,000 years, the Great Pyramids held the title of tallest structures in the world! The Great Pyramid of Giza was the tallest, at 481 feet, and housed tombs for the pharoahs that lived in Ancient Egypt.Khaled Elfiqi/EPA-EFE/Shutterstock