18. Teotihuacan

Teotihuacan is an extensive ancient religious complex near Mexico City. Its many architectural marvels include the enormous Pyramid of the Sun, one of the grandest monuments ever erected. It likely dates back to the early 2nd Century BC. However, little is known about the ancient people who built it a thousand years before the Aztecs came into power. Pronouncing Teotihuacan tay'-uh-tee'-wah-kahn.

• The Pyramid of the Sun. It is as high as a modern 20-story building, making it the tallest structure in Teotihuacan. Some archaeologists estimate that the Pyramid of the Sun is at least 2,000 years old. No one knows for sure its original purpose or to whom the Pyramid of the Sun it was dedicated (the "sun" designation was bestowed by the Aztecs).

• The Moon edifice at Teotihuacan. At the far end of the main thoroughfare sits the Pyramid of the Moon (named by but not erected by the Aztecs). It is almost as big as the Pyramid of the Sun and would be world famous if the latter didn't exist. Though shorter, it is harder to climb because its step height is appreciably steeper. Once on top, though, you have the best view of the ancient Teotihuacan complex.

• Quetzalcoatl. This is the third major archaeological attraction of Teotihuacan. It is known for its fanciful serpent sculptures.

The population estimates of Teotihuacan in its glory days generally range between 75,000 to 200,000. Those figures would make it one of the world’s largest cities in its time. After its prime time (from around 200 BC to 350 AD), Teotihuacan slowly deteriorated physically and in spirit over the next several centuries, then died.

The Teotihuacan moniker was coined by the invading Aztecs, relative newbies. They did not take possession of the complex until a relatively short time before Cortez invaded Mexico in the 16th century. That was nearly a millennium after the original builders abandoned their religious and commercial center.

The Aztecs used the top of the Pyramid of the Sun as an altar for sacrificing captives of war to the solar god. The hapless souls were marched huffing and puffing up the 247 steep steps to have their hearts ceremoniously ripped out by a priest and their heartless bodies unceremoniously tossed down the sheer sides of the Pyramid of the Sun.

19. Banaue Rice Terraces

The mountainous rice terraces of Banaue and vicinity in the Philippines are mankind's grandest scaled engineering feat. The vertical distance between bottom and top rows exceeds the height of the world's tallest building. If the Banaue terraces were laid end to end, they would stretch half way around the world.

The Banaue Rice Terraces were carved over a 2,000 year span with primitive handtools by the ancestors of the current farmers, the Ifugao tribesmen.

The region has other worth-visiting rice terraces, including those of Batad. Its terraces line a breathtaking amphitheater-shaped slope.

Avoid visiting the Banaue Rice Terraces in the rainy season (summer and fall) when low lying clouds can disappointingly mask the views. Winter is the ideal sightseeing season.

The Banaue Rice Terraces (as well as the other regional ones) are now facing erosion because of a decline in upkeep. A big reason is many of the tribespeople are abandoning their terraced farms to find jobs elsewhere.