First built in 1583 by order of Toyotomi Hideyoshi, Osaka Castle is one of the most characteristic monuments of Osaka. However, with his death in 1598, Tokugawa Ieyasu, while ambitiously trying to become the new Shogun, attacked the castle and virtually destroyed it. Thankfully, Tokugawa Hideata commissioned to have it rebuilt in 1620. The 1665 fire badly damaged the castle after it was hit by lightning. In 1931, its iron-based reconstruction was begun and since 1997 there has been major restoration work which is not yet completed. I recommend visiting in April so you can see the sakura that grows around the moat surrounding the castle.