Manaus, the hub of Amazonia, has its famous opera house (1884-96), built in the jungle on the proceeds of the short-lived rubber boom of the late 19th century. The opera house, now beautifully restored, is notable for its high degree of prefabrication - all the parts were shipped in, including cast-iron classical columns from Britain. It’s relatively small 700 seats), with a good, intimate auditorium. Somewhat touching to find a pair of Margot Fonteyn’s ballet pumps there, preserved in a glass case like a sacred relic. Outside, the perennial problem of what to do with the flytower was neatly resolved by turning it into a tiled dome. Ingenious, though not an option for today’s much taller flytowers.

The city is a busy, rather unsettling place (it is a free-trade zone, and the home of Brazil’s electronics industry) but you get something of a feel for how it once was, by visiting the titanic floating docks (again, British-made) on the river. The architecture afforded by the rows of moored Amazon rivercraft - near-identical modules of floating accommodation joining together in a plug-in, Archigram kind of way - is every bit as impressive as the opera house.