The absolute highlight of our stay in Rio was a ride on top of Corcovado mountain (710 meters high) to see Christ the Redeemer up close. We waited for a long time to make this visit on a sunny day with good visibility. Oh, it was totally worth the wait. The awe when you see the massive 30 metres high statue of Christ with his arms open is hard to describe. Not to mention the stunning view over Rio and Sugarloaf Mountain.
The traditional way to ride on top is to take a tram from Cosmovelho station. It is quite expensive (we paid BRL74 per person for online tickets) but we found it worth it as it climbs slowly past lush rainforest and offers panoramic views over the city. But if you are on a budget, we read that there are good minibus connections from different parts of Rio for BRL30-40.