Close to the Arcos da Lapa [1] is the Catedral Metropolitana (Av. República de Chile 245, Lapa, tel. 21/2240-2669, 7:30 a.m.–5:30 p.m. daily, free), a cone-shaped modernist cathedral that was built between 1964 and 1979. Inside, the sense of spaciousness (it holds 20,000 people!) coupled with pared-down minimalism is conducive to contemplation.
If you visit on a sunny day, you’ll be bewitched by the psychedelic patterns of gold, green, blue, and yellow that are refracted through the four immense stained-glass windows.
A small Museu de Arte Sacra (R$2) includes objects such as the baptismal fonts used to christen the emperors’ offspring and the gold roses Princesa Isabel received from Pope Leo XII after abolishing slavery.
Links:
[1] http://www.moon.com/destinations/brazil/rio-de-janeiro/rio-de-janeiro-city/sights/lapa