Mariana is where Minas Gerais begins, at least on paper. It was the first town the Portuguese founded in the gold country, in 1696, and later the first capital and first bishopric of the whole captaincy. It was named for Maria Anna of Austria, the queen of João V, which tells you who the town was meant to impress. Today it sits at around seven hundred metres in a bowl of green, forested hills, a calm university and mining town of some forty-five thousand people, and it is the natural place to begin the Estrada Real, the old colonial road along which gold and diamonds went to the coast and everything else came back up.
Park somewhere near the central square, Praça Minas Gerais, and walk. The pillory stands in the middle, where punishments were once carried out in public, and two baroque churches face each other across the square like a pair of well-dressed neighbours who have not spoken in a century. The cathedral has a German baroque organ that is still played, and on some days there are recitals. The streets are narrow, steep and cobbled in the old centre, so leave the bike on the edge and wear boots you can walk in.
Be aware that the mining that built Mariana is still its economy. Iron ore trucks share the road, and the 2015 collapse of the Fundão tailings dam, which buried the village of Bento Rodrigues a few kilometres away, is not something locals treat as history. It is worth being quiet and respectful about it if the subject comes up.
For the ride itself, the road to Ouro Preto is a short, pleasant one of nine kilometres or so, with rolling curves through hills the colour of rust and moss. It is also the route of a tourist steam train that runs on weekends, so you may find yourself racing a locomotive. Traffic is heavier in the afternoon and on weekends, and potholes appear without warning, particularly after rain, so keep your speed honest. Fuel, cash machines and plenty of food are all in town; the local places serve the Minas staples of beans, pork, cassava and kale, and a small coffee afterwards is almost obligatory. The dry months from May to September are the best time, with clear skies and cool mornings, while the wet summer brings afternoon downpours that turn those cobbles into glass.