It is nearly carnival time in Brazil. Turn on the radio, and you can abandon yourself to the seductive samba rhythms of 1956. I am in Belém do Pará, the crumbling state capital at the mouth of the vast Amazon delta where equatorial rains arrive on the dot every afternoon, descending with such torrential force that even the ubiquitous urubú, the large black vultures, seek shelter underneath the eaves of the hotel. The city rests until 4 o’clock, when the rain stops, and with the steam still rising from the pavement, it’s time to get back to work.