Two songs wrestle for domination in my head as I step out into the morning heat to walk the beachfront of Rio's Zona Sul.
On one mental radio station, Barry Manilow's infectious anthem "Copacabana" (admittedly about a New York nightclub, but impossible not to connect with this sun-blessed city); on the other, Astrud and Joao Gilberto's bossa nova classic "Garota De Ipanema" ("The Girl from Ipanema").
In a week's time, both songs would be drowned out by the sound of drums, samba, singing and millions of revellers when carnival hits Rio (16-21 February; rio-carnival.net). The stretch of seafront that comprises Copacabana and Ipanema beaches is busy at the best of times – beach life is an integral part of Carioca culture. Rich and poor, young and old flood down from their homes at any given opportunity.
I'm on Manilow's turf first. I meet my guide, Guilherme, at the Windsor Hotel (00 55 21 2195 7800; windsorhoteis.com.br) on Avenida Atlantica, which marks the start of Copacabana Beach. The pavement of the promenade is decorated in Calcada Portuguesa, the Portuguese-style black and white mosaic waves, a tribute to the ocean off Copacabana, one of the world's most iconic beaches. It's not quite as glam as its heyday, but this 4km strip of sand continues to heave with sun-seekers.
We follow the avenue west for a short distance, then turn right at Rua Duvivier, where Guilherme points out Beco das Garrafas (Bottles Alley). "It's empty now except for that strip club," he says. "But there used to be bars here where musicians started bossa nova in the 1960s."
On the corner is Bossanova & Companhia (00 55 21 2295 8096; bossanovaecompanhia.com.br), a small music shop selling bossa nova, samba and other Brazilian music. There are books on Brazil's major players too, including Vinicius de Moraes and Antonio Carlos Jobim who wrote the lyrics and music of "The Girl from Ipanema" respectively.
We walk back to Avenida Atlantica, then take another right on to Rua Rodolfo Dantas, next to the gleaming white Copacabana Palace Hotel, where we pass Mud Bug (00 55 21 2235 6847; mudbug.com.br). Barman Elvaraldo is just opening up. The place is empty now, but Guilherme tells me the bar is always lively at night. "And full of beautiful women," Elvaraldo winks. Elvaraldo claims to make the best caipirinha (Brazil's national cocktail of cachaca, cane sugar and lime) in Copacabana. The secret, he says, is changing the drink according to personal tastes. Big guys tend to like it stronger, he says, while women prefer more sugar.
Back on Avenida Atlantica's beach side, we're accompanied by rollerskaters, cyclists and skateboarders. There are stand-up paddle boarders out on the ocean, and skilled young men and women playing futevolei (volleyball using head, chest, feet, but no hands) on the beach.
At the end of Copacabana, we take a detour to Forte de Copacabana (see The Big Attraction). From the fort, we can see across to the opposite side from Copacabana to Arpoador Beach, which seeps into Ipanema.
To get there, we pass through the Girl from Ipanema park, at which point Astrud Gilberto's tune triumphs over Manilow. The outer wall is covered with graffiti, but the park itself is peaceful and cool. On Rua Francisco Otaviano, Guilherme shows me a small arcade of boutiques. This is where locals shop for rollerskates, skateboards, surfboards and beachwear. It also contains a shop dedicated solely to the Ramones (00 55 21 2523 4604; joeyramoneplacerio.com).
"Music and fashion were always the passion," sang Manilow about Copacabana, but that's more true of Ipanema beach and neighbouring Leblon now. The beaches feel younger, livelier and are filled with beautiful people.
We head in the direction of the twin peaks of Dos Irmaos (Two Brothers) at the end of Leblon beach, past the swanky Fasano hotel (00 55 21 32024000; fasano.com.br). Rainbow flags mark out the gay section of the beach around Lifeguard station 9.
We turn right at Rua Vinicius de Moraes and stop by Garota de Ipanema (00 55 21 2522 0340), which has the music and lyrics of the song writ large on the white exterior. "Vinicius de Moraes used to hang around here. He saw the girl from Ipanema, Helo Pinheiro, passing by, on her way to and from the beach," says Guilherme. The bar is now a restaurant. Next door, is another venue called Garota de Ipanema (00 55 21 2521 3168; garotadeipanemashop.com.br), though this boutique has more right to use the title than most. It is owned by the Girl from Ipanema herself, Helo Pinheiro. She's now 64 and living in Sao Paulo, according to the girls who run the shop.
Back on the beachfront, we continue towards the Canal Jardim de Ala, which connects Lagoon Rodrigo de Freitas with the Atlantic. It's taken three hours to get here from Copacabana. The canal marks the end of Ipanema and the start of Leblon, though the change is almost imperceptible. Here too, there's the thwack of volleyballs, the crash of the tide and the yelps of people playing in the sand and the sea – the real soundtrack of Rio.
You can fly from Heathrow to Rio with BA (0844 493 0787; ba.com) and TAM (020-8897 0005; tam.com.br).
Copacabana Palace (00 55 21 2235 7330; copacabanapalace.com.br), where Manilow penned his famous song, has hosted royalty, presidents and celebrities. Doubles start at R$1,006 (£368), including breakfast.
Bespoke guided walks of Rio de Janeiro can be booked online with Viator (viator.com) and cost from R$210 (£77) for groups of up to six people for half a day.
Brazil Tourist Board: braziltour.com
The Big Attraction
Forte de Copacabana (fortedecopacabana.com), at the end of Copacabana Beach, is a fort that previously defended the coast from invaders. "Si vis pacem para bellum" is written above the main archway, which Guilherme translates as: "If you want peace, be ready for war." The military history is interesting enough, but this is a peaceful place now, a long walkway that quickly feels very distant from the crowded beaches. Confeitaria Colombo (00 55 21 2505 1500; confeitariacolombo.com.br) is a quiet spot for lunch, coffee or a beer with a view of Copacabana Beach –far enough away so that the sun-worshippers are thousands of black dots, the sand stretching all the way along the coast to the base of Sugarloaf Mountain.