Lisbon was originally populated by Romans in ancient times, then by Moors from Africa in the Middle Ages. But the city’s glory days were the 15th and 16th centuries, when explorers like Vasco da Gama opened new trade routes to Asia, making Lisbon one of Europe’s richest cities.

Today, Lisbon is a city of about 600,000 on the yawning mouth of the Tejo River. With its iconic bridge and statue of Christ overlooking its huge port, it welcomes ships from around the globe and still feels like Europe’s gateway to the world.

With its characteristic hills and trolleys, Lisbon has a San Francisco vibe. Today, Lisbon is a ramshackle but charming mix of now and then. Trolleys rattle up and down its hills, noble statues mark grand squares, locals enjoy venerable cafés, and a once-neglected harborfront has been revitalized.

Lisbon’s history is dominated by one cataclysmic event: an earthquake in 1755. It was so strong, they say candles quivered as far away as Ireland. 30,000 people died as two-thirds of the city was flattened. It was actually three disasters in rapid succession: After the quake, fires raged through the city, then a massive tsunami slammed into the harborfront.

The scarred pillars of the Church of São Domingos evoke the horror of that day. It was All Saints’ Day, and most of the population was in church. This is one of the few buildings from before 1755 that survive.

The city was reconstructed under the energetic and eventually dictatorial leadership of its prime minister: the Marquês de Pombal.

Lisbon’s downtown is almost entirely post-1755. The Baixa, or Lower Town, sits between two hills. At the top, the Avenue of Liberty provides Lisbon with a proud Champs Elysées–type spine. With wide sidewalks and plenty of trees, it feels and functions like a park. From there, a series of fine squares are in full bloom for our springtime visit. They lead through one of Europe's first planned city centers to the harbor, and the vast harborfront square. Before the earthquake, this square was the site of a huge royal palace. Today, it’s another wide-open public space.

The grandiose arch stands as an Arch of Triumph. A statue of the Portuguese explorer, Vasco da Gama, represents Lisbon’s trade-fueled Golden Age. And a statue of the Marquês de Pombal recalls the devastated city’s impressive recovery after the quake.

Pombal rebuilt the city on a grid-street plan — fast, cheap, and earthquake proof. The spartan and utilitarian architecture, named “Pombaline” (after Pombal), feels almost military. That’s because it is. The Baixa we see today was reconstructed by Pombal’s military engineers, whose experience was in building garrison towns in Portuguese colonies overseas.

The new Lisbon featured the architecture of conquest — economical and simple to assemble — with all the pieces easy to ship. The 18th-century buildings you’d see in former Portuguese colonies like Mozambique and Brazil are interchangeable with the buildings here in Lisbon.

The buildings are all uniform, with the same number of floors and standard facades. Inside, they were designed to survive the next earthquake. Outside, decoration was limited to wrought iron and tiles.

Lisbon’s churches were rebuilt but had to fit Pombal’s austere scheme. You hardly notice their facades. But stepping inside, Pombal’s austerity is replaced with Baroque splendor.

With its distinctive sidewalks, the downtown feels cohesive. The black-and-white cobbled design is an art form and uniquely Portuguese. To this day, patterns dating from the 19th century must be chosen from a book of traditional designs. Wherever you stroll, don’t forget to look down.