As a warm-up for Chan Chan , head first to the restored Huaca Arco Iris (Rainbow Temple), which was built by the Chimú around A.D. 1200 before being covered, and partially preserved, by desert sands. The temple is guarded by thick, six-meter clay walls, and there are two main platforms inside connected by a ramp.
The first platform contains seven restored adobe panels that are carved with the namesake motif of the huaca, two lizardlike beings with an arching rainbow or serpent overhead. The ends of the rainbow/serpent connect to two human figures dancing below, and the relief is fringed with animal figures, which have been interpreted as both sea otters and squirrels.
The exact meaning of the mural has been lost, but many archaeologists believe the mural represents a kind of rain dance or fertility ritual. The rainbow/serpent and the sea otter are associated with rain and are a recurring fertility symbol of both Moche and Chimú art. The sea otter/squirrel, repeated endlessly at Chan Chan, is also a fertility symbol.
The second platform contains 14 niches that were probably used to store ritual objects such as textiles, shells, seed necklaces, and gold objects. Local legend has it that Huaca Arco Iris was also the home of Takaynamo, the mythical, bearded man who arrived by raft to found the city of Chan Chan .
At the top of the huaca, there was probably a small temple where priests communicated with the gods. Nowadays there is a panoramic view of La Esperanza, a neighborhood of Trujillo  founded in the 1960s by campesinos looking for work in a now-defunct industrial park. Because of combined effects of the 1970 earthquake, terrorism, and Peru’s ongoing economic crisis, La Esperanza has exploded to its present population of 700,000, more than half of Trujillo’s total population.
To get to Huaca Arco Iris, take a one-way taxi for US$1 and have it drop you off (there are plenty of taxis in the area). Or from in front of the Museo Cassinelli , take a blue-and-white combi that says La Esperanza and get off at the quinto paradero (fifth stop). You will see the huaca on the side of the highway, surrounded by walls.