Florianópolis ("Floripa" for short) is a coastal city in southern Brazil, the capital of the state of Santa Catarina. Most of the city's area consists of the island of Santa Catarina, connected to the mainland by two bridges, and only a small part of the island can really be called urban—the rest is full of gorgeous beaches and nature, including a large lagoon. Though famous for its beaches, Floripa also has great hikes and beautiful forested mountains. Here you can enjoy the outgoing culture and natural beauty of coastal Brazil in a less dangerous place than Rio de Janeiro, Fortaleza, or Recife.
Florianópolis gets busy in the summer, when its population of about 500,000 swells with tourists (both domestic and foreign) to 1.5 million. Naturally, this causes lots of traffic and generally strains the local infrastructure, so it's better to come in the off-season if you can. Make sure to visit when the weather is nice so you can enjoy all the outdoor activities.