RIO DE JANEIRO: For most visitors to Rio de Janeiro, and even for many residents, the city's historic downtown is a blur, a canyonland of office towers punctuated by the odd colonial-era church — all to be glimpsed through cab windows en route to the beach.

But downtown, known in Portuguese as "Centro," is Rio's historical hotspot, a motley pastiche of vestiges of the city's 450-year-long past.

For visitors capable of prying themselves off Copacabana's golden sands, the neighborhood is a fascinating detour.

And revitalization projects in the area ahead of the 2016 Summer Olympic Games could help spur its rediscovery.

In the nearby Gamboa neighborhood, a modest museum pays tribute to the dark history of slavery. Rio was once the busiest slave port in the Americas, and the Memorial dos Pretos Novos, or New Blacks Memorial, sits where the bodies of up to 50,000 slaves who succumbed during the punishing journey across the Atlantic were burned and dumped. The memorial itself is underwhelming — dusty display cases and fogged-up windows onto archaeological excavation pits — but it's a moving and sobering stop.

Gamboa is also the birthplace of samba, the syncopated rhythm with African roots that's become Brazil's national sound. Soak up the sounds at Trapiche Gamboa, a dilapidated warehouse that's been converted into a nightclub, with live tunes and fancy footwork. Raucous outdoor samba circles take place Monday nights at Pedra do Sal, a nearby square that was once a slave market and one of the hubs of samba's birth in the early 20th century.

Pedro Doria, a columnist and author of a book about Brazil's early colonial period, said that the Centro has been mostly forgotten by Rio residents and tourists alike. With the rise of 20th century beach culture, "suddenly, the emotional center of the city moved" to Copacabana, Doria said. Centro, with its reminders of Rio's slave past, was rejected as "repugnant."

But the Olympic makeovers may raise its profile. "It's where we come from," he said. "We must embrace it."