The metro system for Rio de Janeiro features two lines and, while that doesn't sound like a lot,…read morethey are two long metro lines. The reason that the lines are mostly linear and closer to the coastline is because Rio is backed by some fairly massive and tall monoliths, mountains, and dense forests, so they city is laid out in sort of a horseshoe.
I had read about how dicey the buses were, and they sort of were, and was expecting to find Metro Rio to be much the same. It's not. It feels safe, it's clean, it's relatively inexpensive, it gets you where you need to go quickly, and interfaces with key bus lines to get you right up to the tourist attractions you want to see. In some cases, you can walk to that tourist attraction. You should still safeguard your valuables on a crowded train and, if you wear your wallet in your back pocket anywhere in Rio, YOU are the idiot.
The two metro lines overlap roughly in the center of Rio, with the city's domestic airport being practically within walking distance of one of the downtown stops - Cinelandia. One line extends upward toward the Zona Norte and features the stop for the Maracana stadium while the other line extends into the Zona Sul, which is where the tourists tend to base themselves.
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The Metro has inched southward, finally ending its run barely into Ipanema at the General Osorio station. If you're on the top end of Ipanema, you can hoof it to where you need to go. If you're on the south end of Ipanema or in Leblon, then an additonal bus trek or taxi ride will probably be necessary. The addition of two stations within the last decade has taken the Metro below Copacabana's Siqueira Campos station. With this extension, it's almost amazing that a quick subway ride can now safely and inexpensively take a person from a few blocks inward from Ipanema's beach to Rio de Janeiro's central business district in about 20 minutes.