Casa Grande Ruins
As Casa Grandé's name implies, not even the Spanish had a very clear idea of what it was or why it was built. Modern-day pseudo-scientists speculate that it was an ancient astronomical observatory, but all that's known for sure is that Casa Grandé is a big, brown, Indian ruin.
It was a lot of trouble for the Sonoran Desert people to assemble the materials and construct the enigmatic "Great House." In fact, the structure appears to date from about 1300 AD, just before a severe period of depopulation vacated the region.
Standing in the middle of nowhere, this crumbling, four-story mud skyscraper has always attracted fans of architectural decay. It was the first prehistoric and culturally significant site protected by the US government, back in 1892. What brings Casa Grandé into the Roadside realm is the gargantuan steel umbrella that towers over it -- built in 1932 by the government to shield it from the sun (rain would have melted it centuries ago). The umbrella cost $28,000 to build -- now it takes substantially more than that to paint it every year.
Informative tours around this and other ruins are conducted hourly, though no one actually goes into the house, "due to safety and resource protection concerns," according to the National Park Service.
Whatever its original function, the ruins of Casa Grandé are well-protected for future generations. For them, its most enduring historical purpose may turn out to be as a tourist attraction.