1) The Grand Canyon, located in Arizona, United States, is a massive and awe-inspiring natural formation carved by the Colorado River. It is approximately 446 kilometers (277 miles) long, up to 29 kilometers (18 miles) wide, and reaches a depth of over 1.8 kilometers (1.1 miles).

2) The construction of the Great Wall of China began in the 7th century BC and was completed over several centuries, spanning thousands of miles.

3) The world's tallest waterfall is Angel Falls in Venezuela, with a height of about 3,212 feet (979 meters).

4) The word "school" contains two vowels: O and O.