The Fortifications of Torres Vedras are a series of defensive structures built in the early 19th century in Portugal. Designed by British engineer William Beresford, these fortifications were constructed to protect Lisbon from potential invasions during the Peninsular War. The system includes a network of forts, redoubts, and trenches, strategically placed in the hills surrounding the city. These fortifications played a crucial role in the defense of Lisbon against the French army led by Marshal Masséna. Completed in 1810, the fortifications successfully deterred the French forces, contributing to their eventual retreat. Today, the site is recognized for its historical significance and is a popular destination for visitors interested in military history.