Plant-covered roofs could help chill Brazil’s

This article originally appeared on Undark.

Sweat was dripping down Luis Cassiano’s face. It was 2012, and Rio de Janeiro’s hottest day to date: At nearly 110 degrees Fahrenheit, the seaside city had just barely beaten its previous record The year 1984 was the setting for this film.

Cassiano and his mother, then 82, had lived in the same narrow four-story house since they moved to Parque Arará, a favela…