Inside the state legislature on Avenida 22 de Enero is a remarkable cycle of murals telling the history of Quintana Roo from pre-Columbian times to the present. Quintana Roo is Mexico's youngest state — it only became a full state in 1974 — so this is also a young history, dominated by chicleros (chewing-gum sappers), the Caste War of the Yucatán, and the early twentieth-century expansion that brought settlers down from the rest of Mexico.
The murals were painted in the late 1980s by Quintana Roo artists in a strong, saturated style that owes plenty to Diego Rivera and the Mexican muralists of the 1920s and 30s. Entry is free during weekday office hours; show your passport at the door, ask the guards for the "murales del Congreso", and you will usually be waved through. Twenty minutes for a careful look.