Ongoing concerns about a possible French invasion resulted in Pendennis's defences being modernised and upgraded in the 1730s and again during the 1790s; during the Napoleonic Wars, the castle held up to 48 guns. In the 1880s and 1890s an electrically operated minefield was laid across the River Fal, operated from Pendennis and St Mawes, and new, quick-firing guns were installed to support these defences. The castle was rearmed during the First World War but saw no action and was rearmed again during the Second World War when it saw action against the German Luftwaffe aircraft, but in 1956, by now obsolete, it was decommissioned. It passed into the control of the Ministry of Works, who cleared away many of the more modern military buildings and opened the site to visitors. In the 21st century, the castle is managed by English Heritage as a tourist attraction, receiving 74,230 visitors in 2011–12. The heritage agency Historic England considers Pendennis to be "one of the finest examples of a post-medieval defensive promontory fort in the country".