This iconic arching iron bridge straddles the Douro River, connecting Porto to Vila Nova de Gaia. Though Porto is known for having quite a few bridges, the Dom Luís I Bridge is especially renowned because it was designed by a student of Gustave Eiffel, the mastermind behind the Eiffel Tower in Paris. Plus, at the time of its completion in 1886, this bridge was the longest iron arch in the world. The bridge accommodates cars on its lower level and Porto's metro on its upper level; pedestrians can walk along the bridge on both levels. Stroll along the upper deck of the bridge and you'll be rewarded with spectacular views of the edifices built into the hillside cliffs that line the river.

Perched on a hilltop standing watch over the city, the Porto Cathedral (known as the Sé) was originally built between the 12th and 13th centuries, and features a variety of architectural styles, including Romanesque, baroque and gothic. The fortress-like church is the largest in the city and one of Porto's oldest monuments; it's flanked by twin towers and has a rather plain stone facade. But inside the Sé you'll find a beautiful stained-glass rose window, a collection of centuries-old sculptures and a silver altarpiece that was once used as the bishop's study. Meanwhile, the cloister boasts cobalt and white ceramic tiles that depict different scenes from religious history. Most travelers say visiting the church and cloister is absolutely worth an hour or two, noting that the exterior is remarkable but the interior is exquisite.

The Crystal Palace Gardens boast green shrubbery, winding walkways, bright flora and bubbling fountains. Bring your camera along because you'll find plenty of photo opportunities here: Everything from the flower varieties to the expansive views of the Douro River beckons for your attention. (And if you're lucky, you may even catch a glimpse of the peacocks that roam the gardens.) The park's name comes from the Crystal Palace that once stood here, though it was torn down in 1956 and replaced with a domed pavilion that houses a sporting arena and a multi-purpose events center. Recent visitors say the pavilion is not worth a visit, but the park should be experienced.

Porto's main thoroughfare, Avenida dos Aliados, features a smattering of cafes, hotels, banks and boutiques all housed in architecturally impressive buildings. Located in the heart of Porto, just southeast of the famous Bolhão Market, this wide avenue is named to honor the Allies of World War I. Most of the buildings showcase intricate design in their cupolas and cornices. Points of interests include Porto's granite and marble town hall (which sits at the northern end of Avenida dos Aliados), General Humberto Delgado Square (marked by a few trees and situated in the center of the avenue) and Liberdade Square (which serves as the anchor to the avenue and is marked by a statue of King Pedro IV riding a horse). The central portion of the boulevard often hosts artists, street performers and festivals.

A visit to Porto wouldn't be complete without a stop to sample the city's most notable export — port wine. You'll find dozens of wine cellars scattered throughout Porto, and there's even a Port Wine Museum dedicated to teaching the history of the port wine trade and production development. But if you're more interested in imbibing, head to one (or several) of Porto's top wineries.

Built on the former site of a Benedictine monastery, the São Bento Railway Station was inaugurated in 1916; today, trains pass through here carrying travelers between Porto and many of its northern suburbs. But you likely won't be visiting here to hop a train anywhere. What's notable about this landmark is its 20,000-some painted blue and white tile panels (known as azulejos) that highlight the history of Portugal. Portuguese artist Jorge Colaço is the mastermind behind this azulejo piece; its tiles were mounted over the course of a decade — from 1905 to 1916. Some of the most impressive scenes include King João I and Queen Philippa standing near the city's cathedral in 1387 and a depiction of the Battle of Arcos de Valdevez.

Scents of sweet fruit, freshly baked bread and aromatic cheeses greet visitors as soon as they enter the Mercado do Bolhão. This open-air market is reminiscent of many you'll find in Europe, with vendors hawking a variety of fresh goods and homemade wares at very affordable prices. The market, which dates back to 1850, is housed behind a neoclassical facade in a two-story building in the heart of Porto. While some recent visitors say the building is in need of some renovations, they note the bustling energy of the market and delectable treats make up for the aging facility.

Porto's location along Portugal's northwestern coast grants the city access to some prime beachfront. If you find yourself experiencing a sunny day, visiting Portugal's northwest coast is a great way to pass the time. In Foz, located east of the city center along Avenida do Brasil, you'll find a handful of small beaches, like Praia do Molhe and Praia de Gondarém. Though picturesque, the terrain just offshore is a little rocky, so swimming isn't advised. But you can still bring a towel to lie on the sand, soak up the sun and dip your feet in the cool Atlantic for a little refreshment. Speaking of refreshment, this area of Porto is also packed with plenty of beachfront bars, restaurants and cafes — it's quite a popular place to enjoy the outdoors both day and night.

Everyone knows the old adage, "don't judge a book by its cover" — the notion couldn't be truer in the case of the Igreja de São Francisco. This church looks rather plain on the outside, sporting a stone facade with elements of gothic and baroque styles, but step inside and you'll be greeted with gold: lots and lots of it. An abundance of gilt wood carvings (reportedly more than 800 pounds of gold) make up the columns, vaulted ceilings and walls of this UNESCO World Heritage Site church, which started to take shape in 1245. A traveler favorite amid the luster is the Tree of Jesse, a massive family tree sculpture that traces Christ's genealogy and dates back to 1718.

A bookstore may not seem like one of the most necessary things to see in a new city, but when it's consistently named one of the world's most beautiful, it's worth a look. Situated among the cafes and shops along Rua das Carmelitas in downtown Porto, Livraria Lello easily stands out with its chalk white, neo-gothic facade featuring intricate carvings and two painted ladies (representing science and art). Step inside and you'll be even more impressed. The bookstore's interior is adorned with rich wooden paneling and colorful stained glass windows, and boasts a regal ruby red staircase. As for the books, you can peruse an assortment of Portuguese fiction and non-fiction works, as well as a selection of books in English and French.

One of the most-visited sites in Porto, the Palácio da Bolsa is renowned for its exquisite neoclassical facade and ornate gilded Arabian Hall. This massive building — located in the historic center of Porto — once acted as the city's stock exchange, wooing European bankers and investors alike. Today, you can tour the interior with a guide and see the glass-domed Pátio das Nações (Hall of Nations) and the magnificently golden Salão Árabe (Arabian Hall, which was designed to mimic the Alhambra Palace in Granada, Spain), as well as the numerous portraits that adorn the walls.

The Fundação de Serralves comprises a park, a villa and a contemporary art museum all set on nearly 45 acres of land in western Porto. Billed as a cultural institution, the foundation aims to "raise the general public's awareness concerning contemporary art and the environment." The villa and park were the first to open (in the 1930s); the villa is often touted by architecture experts and historians as the most noteworthy example of an art deco building in Portugal and it was declared a national monument in 2012. Inside, the villa is laid out like a private residence (as it was originally such) and hosts temporary art exhibits throughout the year. Situated on one of the highest points of the complex, the villa overlooks the park, which features lush gardens, exotic plants, winding pathways and even a farm. Permanent sculptures pepper the premises as well. Meanwhile, the Serralves Museum opened in 1999 and boasts 14 exhibition galleries across three floors. Today, the museum features rotating art exhibits, music and dance performances, and educational programs.

Founded in 1833, the Museu Nacional de Soares dos Reis was Portugal's first public art museum. Art lovers will appreciate the expansive collection housed here, as well as the ornate building itself. Occupying a former royal residence, the museum features much of the work of its namesake, António Soares dos Reis, including his famous marble sculpture, "O Desterrado" ("The Exiled"). Inside the museum you'll find a vast selection of Portuguese paintings and sculptures from the 16th to 20th centuries created by a variety of artists. The museum also features furniture, jewelry, fabric work and glassware. Recent visitors noted they were pleasantly surprised at both the beauty of the extensive collections and the regal building, calling the museum "a real gem."

While Portugal may not be as well-known for having avid soccer fans as Spain or England, the Portuguese still love their futebol. Porto's home team, F.C. Porto, is one of the country's "Big Three" — the three most successful multi-sports clubs in Portugal — and plays in Dragão Stadium. You can take a tour of the stadium: A guide will escort you to see the presidential box, locker rooms and players' benches. Or, skip the tour and explore the on-site museum, which highlights F.C. Porto's history and showcases trophies like the UEFA Cup and European Super Cup. But if you really want to experience the stadium come alive, get a ticket to a soccer match.