The cathedral on Plaza Colon is the kind of building you do not expect to find in northern Chile. It is built entirely of cast iron and steel, prefabricated in Gustave Eiffel's Paris workshops and shipped out in pieces in 1876. The Neo-Gothic styling is conventional — pointed arches, a small rose window, a slim steeple — but the construction is anything but: every wall and column is bolted iron, painted off-white inside, and the roof is corrugated metal.
Eiffel built three such prefabricated churches for South America in the 1870s, and this is the only one still on its original site. It is dwarfed by the rocky bulk of the Morro behind it; the contrast is one of the city's signature views. Mass is held daily; out of those hours the doors are usually open for visitors.