Making last-minute preparations for my visit to Brazil, to give a short course on algebraic cycles and birational geometry, I decided to visit the US State Department website for any travel advisories. Almost everything there was as expected. Almost.
Visitors should also remain alert to the possibility of manhole cover explosions. There have been multiple manhole cover explosions in Rio de Janeiro in the past few years, with a higher incidence in the Centro and Copacabana neighborhoods.