Wandering the colonial quarter — Colonia's Barrio Histórico is made for aimless strolling — a small, leafy grid of rough-cobbled streets, low colonial houses in ochre and white, and small plazas, where the Portuguese and Spanish pasts mingle (the irregular Portuguese-laid cobbles differ from the neat Spanish ones). Walk the famous Calle de los Suspiros (Street of Sighs), a short, steeply cobbled lane down to the river, climb the old lighthouse for the view over the red roofs and the Plata, and pass through the Portón de Campo city gate and its drawbridge. There's no hurry here; the town is the experience.
Sunsets on the river — Colonia's other great pleasure is the Río de la Plata, so wide it looks like the sea, and the sunsets over it are famous — the whole town drifts to the ramblas and the old port at dusk to watch the sky and water turn gold and pink. Walk the riverfront promenades, sit on the wall with a mate or a wine, and let the light do its work. It's the classic end to a Colonia day, and reason enough to stay past the last ferry.
Vintage calm and cafés — Part of Colonia's charm is its timeless, unhurried mood — old vintage cars parked (some running, some purely decorative) along the lanes, leafy squares, artisan and antique shops, and cafés and wine bars in the old houses. It's a place to slow right down: a long lunch, a wander, a coffee, another wander. Rent a bike or a golf-cart to potter further out. The atmosphere — gentle, green, faintly faded — is the point, and it's why a quick day trip so often turns into an overnight.
Uruguayan food, wine and mate — Colonia eats Uruguayan, which means meat and warmth — the asado (barbecue) from the parrilla, the chivito (Uruguay's mighty steak-and-everything sandwich), milanesas, and dulce de leche in the sweets, with Uruguay's own Tannat red wine and the ever-present mate (the shared herbal tea Uruguayans drink constantly). The old-town restaurants and wine bars serve it in lovely settings. Eat a chivito or an asado, sip a Tannat at sunset, and you've tasted the country.