Rua do Amendoim is a short suburban street in the Mangabeiras neighbourhood that has become a low-grade tourist attraction because of an optical illusion. The street looks unambiguously like it slopes downwards, but a car put in neutral at one end will roll the other way, apparently uphill. It is a classic "gravity hill" effect — the surrounding landscape gives a misleading horizon line and the brain assumes the wrong slope.
The visit is more of a curiosity than a destination. Drive to the marked spot, put the car in neutral, watch it ease the "wrong" way, take a photo, and move on. Best done outside rush hour, when local traffic makes the road awkward to stop on.