Near the Stock Palace and the Douro River is another UNESCO World Heritage site that is well worth visit while in Porto, the Monument Church of St Francis, or Igreja Monumento de São Francisco. This church built around the 14th century has one of Europe's most sumptuous and extravagant interiors. Here, all that glitter is, in fact, gold! Its interior is covered in gilded woodwork, and rumour has it that it was used around 400 to 600 kg of gold to decorate it. Hence why the St Francis Church is also known as "The Golden Church". Another highlight of this church is its impressive Tree of Jesse, a wooden sculpture carved by Filipe da Silva and António Gomes in 1718 depicting the ancestors of Jesus Christ, shown in a branching tree — considered to be one of the best in the world of its kind. Under the church, you will find the catacombs, where the Franciscan monks along with the members of Porto's noble families are buried.

At the Mercado do Bolhão, you will find a bright and vibrant open-air market brimming with fresh produce such as olives, cheese, and freshly baked bread. Known for its lively atmosphere, this is a great way to start the day, grab some breakfast or stock up on supplies for a day of sightseeing.

At the northern end of Largo do Senado you can find this superb 16th century Baroque church said to be the most beautiful in Macau. Make sure not to miss the small museum in the back that collects around 300 artefacts dated from 17th to 19th century.

These fascinating tunnels were originally built during World War II in order to protect oil supplies from the Japanese bombings, though they were never used for that purpose. Today, two of the tunnels have been opened to the public and feature a collection of interesting photographs depicting life in Darwin during the war.