An hour's drive west of La Paz, Tiwanaku (also spelled Tiahuanacu) is Bolivia's most important archaeological site. Partial excavations have revealed the remains of five different cities, one built on top of the other. The site's most impressive monument is the 10-ton La Puerta del Sol (Gate of the Sun), an imposing stone fixture believed to be a solar calendar built by a civilization that surfaced around 600 BC and mysteriously disappeared around AD 1200. The gate is
part of an elaborate observatory and courtyard that contain monoliths and a subterranean temple. Although the site lacks the sweep and splendor of Peru's Machu Picchu, it does provide a glimpse into the ancestry of the Aymara, who still farm the ingeniously constructed terraces built centuries ago.
Start your visit with the museum next to the ruins. It displays artifacts found at the sight, the most spectacular of which is a 20-ton, 7.3-meter- (24-foot-) tall monolithic statue sculpted out of red sandstone. The monolith was discovered by an American, Wendell C. Bennett, during excavations in 1934, and since then had been on display in an open-air garden museum in La Paz, where it was being seriously eroded by weather. It was returned to Tiwanaku when the new indoor museum opened in 2002. Admission to the ruins and the museum is around (Bs)140 and guides are available at the entrance for (Bs)70.
Bring a warm sweater or poncho—the area is frequently windy and cold, as there are no trees to break the wind. If you are in La Paz in June, go out to the site for dawn on the day of summer solstice; it's a moving experience.