Buenos Aires is the capital that looks across a river wide enough to be mistaken for the sea. The Río de la Plata is brown, shallow and enormous, and the city that sits on its western shore has always seemed to face outward, toward Europe. Pedro de Mendoza first tried to found a settlement in 1536 and failed, and Juan de Garay refounded it in 1580. Since then the port has grown into one of the great cities of the southern hemisphere, with about thirteen million people in its wider area, wide avenues designed on a Parisian scale, and cafés that keep a table for you all afternoon.
Start with the middle. The Plaza de Mayo holds the pink Casa Rosada, the cathedral and the weekly circle of the mothers whose children disappeared under the military dictatorship, a quiet and moving ritual. San Telmo has cobbled streets, antique shops and a Sunday market. La Boca has painted metal houses and a football stadium that shakes when the crowd sings. Recoleta has a cemetery of ornate marble tombs that is a city in itself. Avenida 9 de Julio is among the widest streets in the world, and crossing it takes more than one set of lights. Tango is the music of the neighbourhoods, and you will hear it in bars as often as in shows.
For a rider the city is a challenge in the best and worst senses. Traffic is intense, motorcycles weave through lanes with little ceremony, and rain makes the old tramlines and painted markings slick. Leaving is easier by motorway: the Panamericana to the north, the autopista to La Plata in the south, or the roads west to the pampas, which run flat and straight for hours through cattle country. Tolls are common and cash helps. This is also the starting point for the ride to Fray Bentos in Uruguay, crossing the river by a bridge far upstream or by ferry, so check border papers and insurance in advance.
Fuel is everywhere and usually easy to buy. Eat steak at least once, preferably in a plain parrilla with checked tablecloths, and drink maté with locals if you are offered it. Spring and autumn are the best seasons. Summers are sticky, and winters are mild but damp. Do not leave the bike on the street overnight in some neighbourhoods; ask your hotel about secure parking.