4. Tikal, Guatemala (peak of development about 800)

Tikal was one of the most powerful city states of the classic Maya, in the highlands of present day Guatemala. It consists of many groups of platforms, pyramids, and low buildings on knolls and shoulders of land, sitting above the surrounding swamps and jungles.

The Great Plaza in the center of Tikal is flanked by the pyramids of Temple 1 (Giant Jaguar) and Temple 2, facing east and west, and also the low North Acropolis and palace building of the Central Acropolis on the south, all forming a dramatic and exciting civic and religious space. The central pyramids each have only one impossibly steep stair, facing each other and rising symmetrically up from the plaza. At the top is a small room with an elaborate roof comb headdress. Should you make the climb, you are rewarded with an astonishing vista of the tops of dozens of other pyramids, many unexcavated, rising above the dense jungle.

The architects of Tikal and other Peten Maya sites, habitually thought in terms of groups of platforms and buildings, rather than isolated structures. Exterior space is much more important than interior rooms, which are generally small cellular spaces in a row. Assemblages of several buildings often serve as markers of significant positions of the sun on the horizon, or perhaps the stars. Tikal also contains a ball court that was used in the ubiquitous ancient Mayan ritual game, and structured causeways that lead to many outlying structures. Mayan hieroglyphs, carved on stelae (vertical rock slabs) around the site, have recently been deciphered, and mostly tell of ancient Kings and their conquests against neighboring cities. Today, Tikals remote location and towering limestone pyramids make a powerful impression.

Address: Tikal National Park, GuatemalaPhone: 502-7920-0025Web information: http://enjoyguatemala.com/tikal.htmHours: Monday-Sunday: 6 am to 6 pmAdmission: 50 Quetzales($6.35)

5. Scrovegni Chapel, Padua, Italy (1300-06)

Few buildings illustrate the potential for the integration of art and architecture as well The Scrovegni Chapel. This small early 14th century chapel is the masterpiece of Giotto di Bondone (1267-1337), a Renaissance man before the Renaissance. A master-builder and painter, Giotto revolutionized western sight and philosophy through his early developments in perspective drawing. The chapel, a simple vault, is built into the ruins of the ancient Roman amphitheater, transforming a monument to brutality into a place for forgiveness. (Reginaldo Scrovegni, whose son built the chapel, was consigned to hell by the poet Dante.) The extent of Giottos frescoes make the size and scale of the interior all but impossible to fully gauge. No photograph can capture their intense blue. This color alone could make a Hells Angel cry and alone is worth the trip to Padua.

A fabulous website provides information on the history and restoration efforts, as well as information on visiting the chapel. Dont miss the virtual tours. giottoagliscrovegni.it/eng/home.html

Address: Piazza Eremitani 8, Padua (off Corso Garibaldi)Phone: 011-39-049-2010020Web information: See aboveHours: Daily, 9 am to 7 pm (closed Jan. 1, May 1, Dec. 25 and 26)Admission: Adults 11 Euros ($13.50); students and seniors 4 Euros ($4.90); children five and under free

6. Mesa Verde, southwestern Colorado (abandoned just before 1300)

These astonishing Pre-Columbian dwellings, built on cliffs in shallow caves by people known as the Anasazi, were rediscovered in 1888 by a rancher looking for lost cattle. In the canyons of Mesa Verde are hundreds of caves, and during the height of the areas occupation (the 13th century), dwellings were built in almost every cave. The majority of tree ring dates obtained so far from the sites fall between 1230 and 1260, indicating this was a time of great construction activity. Remarkably, many of these extensive and beautiful sites were only lived in for one or two generations, as the inhabitants struggled with drought and possibly defense.

The cliff dwellings range in size from a single room to the largest, called Cliff Palace, which has about 200 rooms and 23 kivas. Kivas are the remarkable underground Anasazi religious spaces (one can be entered at Spruce Tree House, one of the dwellings open to the public). The buildings were mostly made of ledgestones gathered from the site, and were originally covered with mud plasters, some with painted designs. The caves provided some shelter from the elements, and some of the dwellings were situated so they were shaded from the hot summer sun, but warmed in winter, when the sun angle is lower.