Although not the largest Mayan city—at its height, a population of 24,000 lived in the surrounding region, as compared to more than 100,000 at Tikal—Copán was, as famed archaeologist Sylvanus Morley put it, “the Athens of the New World.”
For reasons that remain mysterious, Copán was the principal Mayan cultural center during the 400 years when the city was at the peak of its development, far ahead of other larger and more powerful Mayan cities in its development of sculpture, astronomy, and hieroglyphic writing.
The ruins are open 8 a.m.–4 p.m. every day. Entrance to the main park plus Las Sepulturas  is US$15, and the Museo de Escultura Maya  is another US$7 (all highly recommended). It’s another US$15 to enter the tunnels — pretty pricey for the experience. It’s very nice to get in right when the gates open.
In the early morning hours, you’ll be able to enjoy the ruins in relative solitude, and you’ll have good low-angle light for photographs. This is also the favorite time for a group of white-tailed deer that live in the woods to come out and wander through the ruins.
When walking around the ruins, refrain from walking on stairways that have been roped off.
Try not to lean on sculptures, stelae, or buildings — salts from your skin can corrode the stone, especially when multiplied by the 60,000 or so visitors who come to Copán each year.
It should go without saying, but let it be said: It is illegal to remove any stones from the park.
Two pamphlet-guides to the ruins are sold at the ticket office: History Carved in Stone, by William Fash and Ricardo Agurcia Fasquelle, and Copán, Legendario y Monumental, by J. Adan Cueva. The former, written in English, has an excellent interpretation of the growth of the city and advances in archaeology, but does not discuss each monument individually. The latter, in English and Spanish, is weak on recent advances in archaeology, and although it does give descriptions of many major sites, they are often incomplete and not entirely useful.
Guides can be hired at the site for US$25 for a two-hour tour. Some of these local men have worked at the ruins for many years and have a positively encyclopedic knowledge about the archaeology of Copán — not just the names of buildings, but explanations on how archaeological views changed, when certain discoveries were made and why they were important, and all sorts of other details. In addition to providing information on the ruins themselves, guides often relate interesting local legends and tall tales about the area. Casual tourists may find their brains spinning with the endless stories of temples, rulers, and altars, but if you’re really curious to learn more about Copán, you are definitely encouraged to hire a guide. They charge an extra US$10 to accompany you to the Museo de Escultura Maya , and US$15 for Las Sepulturas  — both worthwhile expenses.
Although English-speaking guides are available, their language abilities vary. If your Spanish is nonexistent, check beforehand to make sure you and your guide can communicate well. You may want to consider contacting the Asociación de Guías Copán (tel. 504/651-4018, guiascopan [at] yahoo [dot] com) ahead of your visit to reserve a guide in English, particularly during high season (Holy Week, July, and August). Guides who speak other languages are available as well.