The US dollar black market doesn’t just thrive in Buenos Aires, it’s published in the paper every morning. Swinging by one of the city’s newsstands, you’ll find the official peso to dollar rates published next to the ‘dólar blue’ rates at the top of the morning edition of La Nacion, and if you walk downtown to Calle Florida, the arbolitos that stand planted on the busy commercial street greet any foreigner they see with barks for “Cambio! Cambio! Cambio!” Currency restrictions have gotten more stringent in Argentina in recent years as the government struggles to prop up confidence in the peso by restricting the dollar. The restrictions have held the official rate down to around 8 to 1, but the blue rate at around 10 to 1 is so favorable that dollars determine tourism prices and denominate everything from technology purchases to property.

Confidence in the dollar and lack of faith in the domestic peso is deeply woven into the culture of Argentina. While it strikes foreigners strange that a vast portion of the country thinks in dollars, periods of inflation are so frequent in Argentinian history, those who don’t have an escape from the inflationary currency are quickly left behind. Inflation over the past year reached 100% by private estimates, but that pales in comparison to the economic crisis of 2001 when Argentina declared bankruptcy and ruptured peso parity with the US dollar, freezing bank accounts for many. At the peak of the crisis, when one woman couldn’t get money from her account, she doused herself in gasoline in the middle of the bank floor and lit herself on fire. A decade earlier in the late 80s, Argentina saw one of the worst periods of inflation in modern history, reaching 5000% over the course of 1989, resulting in massive food shortages and riots around the country. Haunted by decennial crises Argentinians rationally hoard dollars, a sum total around $50 billion hidden in walls and under sofa cushions.

Those who have the means and access, look for banks outside of the country denominated in dollars or euros and some choose to invest in domestic property (also denominated in dollars, or pesos at the blue rate), but many turn to cuevas (caves) or arbolitos (little trees) to guard their savings in physical dollar bills.

This means that the black rate is dependent on the flow of physical dollars into the country. Each physical dollar needs to come from abroad, either withdrawn from an ATM in Uruguay and brought back across Rio de la Plata, or flown in from the United States or Europe stored in wallets and stuffed in underwear.