Many East Coast cities developed on waterways that allowed access to the Atlantic Ocean and trade with other coastal cities around the world. Philadelphia, Pennsylvania, dates back over 300 years.

Mexico's history is richly preserved. An example is the main pyramid at Chichen Itza, an ancient Mayan city on Mexico's Yucatan Peninsula.

North America has several active volcanos. This one, Popocatépetl, is one of Mexico's most active. In 1997, Popocatépetl threw ash almost 10 miles into the air. Ash fell on Mexico city, 45 miles (72 km) from the volcano, and closed the city's airport.

Most towns and cities in Mexico have squares, such as this one in Guanajuato. A square is a central open area where people meet friends or stop to rest.