The most spectacular events are the parades of the samba schools, which are held in a unique venue designed by renowned Brazilian architect Oscar Niemeyer.The Sambódromo is a long parade route lined by stadium-style boxes designed so that up to 50,000 spectators can watch the parades of brilliantly costumed dancers as they compete.Rio de Janeiro's setting between the mountains and the sea is so spectacular that UNESCO cited "the staggeringly beautiful location for one of the world's biggest cities" in naming Rio a World Heritage Site.
The Corcovado rack railway chugs from Rua do Cosme Velho up the 3.5-kilometer track to the statue, through the Tijuca National Park.
One of the world's most famous pre-Lenten celebrations - as well-known as those in Venice and New Orleans - takes place each winter in Rio de Janeiro.
It sits on a point of land that projects out into the bay and wraps around its harbor, and is connected to the city by a low strip of land.
You can take a cable car from Praça General Tibúrcio to the top of the Morro da Urca, a lower peak from which a second cableway runs to the summit of the Sugar Loaf.
You can learn about this and other military history at the Museu Histórico do Exército (Museum of the History of the Army) now housed here.
Outside, on the fort grounds, are artillery pieces from the late 19th and early 20th centuries.
Tijuca National Park protects the Tijuca Forest and several viewpoints overlooking the city, and surrounds Cristo Redentor, the giant-sized statue of Christ on Corcovado.
To explore the park, you can leave the train up to Corcovado at a midpoint and follow the road through the forest.
On Cara de Cão are three forts, of which the 16th-century star-shaped Fort São João is open to the public.
The giant statue of Christ overlooking the city from the 709-meter summit of Corcovado is almost as widely recognized a symbol of Rio as the distinctive shape of Sugar Loaf.
At the far end of the beach, Copacabana Fort dates from 1914 and was the scene of a 1922 revolt of officers, who took over the fort and turned its artillery on the city.