Colonia del Sacramento is an ideal destination if you're combining a trip to Uruguay and Argentina. That's because large boats called buques make daily trips to Buenos Aires from Colonia's port. The passage takes just one hour and is a smooth ride across the Plata River. A lot of people who visit Buenos Aires take advantage of the opportunity to spend a day in Colonia and return to Argentina for the night. If you choose to drive from Montevideo to Colonia, it's a 180 km (112 miles) drive along a beautiful highway that is nearly perfectly straight.

This small city is the only one in Uruguay that was founded by the Portuguese. A few months after it was founded in 1680, it was taken over by the Spanish. It changed hands between the Portuguese and Spanish seven times until 1778, remaining a Spanish city thereafter until Uruguay became independent. That's why Colonia brings together Spanish architecture with Portuguese details – like Portuguese-style ceramic tile and stone streets. The Santísimo Sacramento Basilica is on the main square and is the oldest church in Uruguay – it was founded in the same year as the city. The church was destroyed and restored numerous times in the wars between the Portuguese in the Spanish.

Colonia del Sacramento became a UNESCO World Heritage Site in 1995. Because of the numerous wars, walls were built around the city and the city walls and gate are still well preserved. A drawbridge takes you from the main square to the historic neighborhood.

Another place to visit is Plaza de Toros, a small stadium built for bullfighting that holds 10,000 spectators. It stopped being used in 1912. You also won't want to miss the lighthouse built in 1845. The long walk up the stairs is worth it – there's an incredible view of the city and the Plata River.