Dois Irmãos (the “two brothers”) is what they call the bookend mountains framing Ipanema and Leblon beaches. For some years now, these peaks have been a hit with hikers, on an adventure that begins even before trekking, because to get to the trailhead you first ascend to the favela called Vidigal—one of Rio’s most peaceful, by the way—either on foot or by moto-taxi. The way is rough but accessible, steep but doable for those in reasonable shape, and the 45-minute walkabout offers several stops at scenic overlooks, each as spectacular as the next. To the left lies the Pedra da Gávea and Rocinha, another sprawling favela; the Atlantic extends to the right. When you get to the top, the views take your breath away—just as soon as you catch it.