Brazilians had been hunting for oil since the empire. Dom Pedro II granted an Englishman, Thomas Denny Sargent, the right to extract oil and other minerals in the south of Bahia, and nothing came of it. In 1892 Eugênio Camargo put a drill into Bahian ground and pulled up clayey sand. By 1907 the Mineralogical Service of Brazil had joined the effort and widened the areas under analysis, which for a long while only meant widening the territory in which nothing was found. The search outlasted the empire and it outlasted the First Republic. Generations of prospectors spent their working lives on the proposition that a country that size had to have oil under it somewhere, and died without seeing it proved.

Work at Candeias began on 2 April 1941, though the bit did not actually turn until 30 June. The well carried an unglamorous name — Candeias 1, C-1 — and it was completed on 31 December, two and a half weeks after the discovery it is remembered for. What separated C-1 from Lobato was arithmetic as much as geology. Lobato had proved that Brazilian oil existed; Candeias proved that Brazilian oil could be pumped and sold. C-1 became the first commercial oil well drilled on Brazilian soil and the heart of the country's first oil field. The distinction sounds like bookkeeping, and retellings blur it constantly, but it is the whole point. Nineteen thirty-nine gave Brazil hope. Nineteen forty-one gave it an industry.

A field needs somewhere to send its crude. Bahia's oil workers' union, Sindipetro, recorded how the Candeias discovery and the development that followed pushed the country toward building a refinery of its own, and in 1950 the Landulpho Alves refinery rose at São Francisco do Conde, the next municipality over. On 23 June 1952, President Getúlio Vargas came to Candeias in person and used the visit to argue for a state monopoly over Brazilian petroleum and for a national oil company to run it. The campaign behind him had a slogan that every Brazilian still recognises: o petróleo é nosso, the oil is ours. Petrobras was created on 3 October 1953, inheriting a country that produced roughly 2,700 barrels a day.

The Instituto do Patrimônio Artístico e Cultural da Bahia listed the well as protected heritage in 2011, on the reasoning that you cannot explain Petrobras without it. Beside the wellhead, Petrobras built a monument dedicated not to executives or geologists but to the first oil workers — the men who ran that secondhand rig through the second half of 1941 with no assurance that this hole would end any differently from the sixty years of holes before it. Their refinery outlived the monopoly the well helped create: Petrobras sold Landulpho Alves in 2021, and it operates today under the name Mataripe. The wellhead itself is a modest thing to stand in front of. Very little about Brazil's twentieth century makes sense without it.