The Luís I Bridge is an iconic iron bridge in Porto, Portugal, offering stunning views of the Douro River and the city. Pedestrians can walk across both the upper and lower levels, but the upper level may not be suitable for those with vertigo. It's generally accessible, though some areas around the bridge may have cobblestones or uneven surfaces. Solo exploration is common and rewarding, allowing you to take your time and enjoy the views, though guided tours are available to learn more about its history and construction. There are no seasonal restrictions, but it can get crowded during peak tourist season (summer). A walk across the bridge is free, but tours and activities in the area have varying costs. A typical visit can last from 1 to 3 hours, depending on whether you walk across both levels and explore nearby attractions.