The Maya haven’t disappeared.

Just as the fall of Rome didn't meant the end of Romans, the decline of great Maya metropolises, such as Guatemala’s Tikal, which reached its apex in the ninth century, doesn’t mean the indigenous people have vanished. About 40 percent of Guatemala’s 14 million people are Maya, and southern Mexico and the Yucatán Peninsula are home to many more predominantly Maya regions.Not only are the Maya enduring almost five centuries after the Spanish conquest, but their cultural traditions, agrarian lifestyle, and celebratory festivals continue on. There are more than 20 distinct Maya peoples within Guatemala, each with their own culture, style of dress, and language, and hundreds of thousands more Maya live beyond the borders.

The Maya don’t believe the end of the world is coming.

Apocalyptic movies may suggest the Maya believe the end of the 5,000-plus-year calendar—December 21, 2012—is an end-times moment, but that’s just not true. Many Maya may celebrate the beginning of the next 5,125-year cycle of the Long Count calendar just as we celebrated the new millennium. But they don’t believe the end of the world is on the horizon. If anything, they’re hopeful that a new era will usher in an age of higher consciousness, greater peace, and enhanced understanding among the diverse peoples on the planet.

The ancient Maya developed the concept of zero.

The Maya’s remarkable Long Count calendar relies on zero as a placeholder. While the idea of zero may have originated in Babylonia, it was independently conjured by the Maya, likely in the fourth century.Zero in the Maya written language was often represented by a shell-shaped glyph. The Maya numerical system is based on factors of 20. So Maya numbers are composed of units of 1, 20, 400, and so on. To write the number 403, for example, a Maya would use a symbol for one unit of 400, zero units of 20, and three units of 1. That’s how they derived the concept of zero.

Much of the Maya world remains underground.

Major Maya sites, like Palenque in southern Mexico and Chichén Itzá in the north, have been largely excavated, but others remain buried. Even Tikal, the most famous ruin in Guatemala, has mounds that conceal what could be great temples.Lesser visited Maya sites, such as the sprawling El Mirador and Uaxactún, both just north of Tikal in Guatemala’s Petén jungle, are only fractionally unearthed and thrilling to visit for the sense of discovery. Belize, too, has its share of barely excavated ruins, such as Altun Ha, just 30 miles from Belize City. You can see monumental pyramids at all these sites, but so much more remains.

The Maya were fans of the sauna.

Ancient Maya enjoyed steamy stone saunas, known as temascal in Yucatán Peninsula, or tuj in the Maya language of Quiché. The Maya sauna, or sweathouse, is still popular and offered to visitors at hotels and resorts throughout the Maya world.Ancient Maya cities built saunas of stone or adobe mud—these were used for health and spiritual fulfillment. The Maya combined water with fire-heated rocks to create steam, and sometimes elder leaves were added to the mix. “After a time you'll note that you're sweating,” blogged a Peace Corps volunteer in Guatemala in 2011, “and that a layer of grime, what they call grasa, seems to be lifting itself from your skin—and your mind.”

The land of the Maya is volcanically active.

A chain of volcanoes runs through Guatemala and several of these remain active. From the tourist-friendly town of Antigua Guatemala, you can often see Fuego volcano puffing out plumes of smoke or jettisoning fiery tendrils of lava, especially vivid at night. Not far from Antigua (about a 90-minute drive) is Pacaya volcano, which has been erupting continually for years.Travel agents in Antigua sell day tours on which you can hike to within a few yards of molten lava. I kept my distance but our guide got so close he lit his cigarette with the lava’s heat; the ground was so warm his sneakers started to melt.

White-water rivers traverse the Maya world.

When most people think about white-water rafting in Central America, they think of Costa Rica. But Guatemala has world-class boating, such as the intermediate (Class III-IV) Río Cahabón, which is not just an exhilarating ride but a way to meet local Maya who live on the banks of the jungle waterway.The Usumacinta River runs along the border of Mexico and Guatemala—river trips stop at ruins such as Piedras Negras, on the Guatemala side of the border. An American woman, Tammy Ridenour, has been running river trips and leading adventure tours in Guatemala for more than two decades, www.mayaexpeditions.com.

Blood sports were important in the ancient Maya world.

Many Maya cities contained a ball court where teams of the best athletes would try to vanquish each other. The heavy, often soccer-size ball was made from hard rubber; some scholars think that human skulls were sometimes placed inside the balls.The games were cultural spectacles followed by human sacrifices. Not everyone thinks it was the losers who were offered to the gods. A guide in Tikal firmly believes it was the winners. “Morir en Tikal es un honor,” he told me atop a lofty temple. "To die in Tikal is an honor."

Some Maya pyramids were built to reflect astronomical events.

It’s no secret that the Maya were advanced astronomers—what’s lesser known is that many great Maya structures, such as El Castillo (Temple of Kukulcan) pyramid at Chichén Itzá, reflect astronomical events.During equinoxes, an undulating shadow called the “serpent” slithers along the side of Kukulcan’s northern staircase. This is caused by the angle of the sun hitting the nine main terraces.Also at Chichén Itzá is El Caracol, known as the observatory, which is linked to the orbit of Venus. El Caracol’s front staircase targets Venus’s most northern position, and the corners of the building align with the sun’s position at the summer solstice sunrise and winter solstice sunset.