After unifying Japan in the late 16th century, General Toyotomi Hideyoshi built this castle (1583) as a display of power, using, it's said, the labour of 100,000 workers. Although the present structure is a 1931 concrete reconstruction (refurbished in 1997), it's nonetheless quite a sight, looming dramatically over the surrounding park and moat. Inside is an excellent collection of art, armour, and day-to-day implements related to the castle, Hideyoshi and Osaka. An 8th-floor observation deck has 360-degree views.
Hideyoshi's original granite structure was said to be impregnable, yet it was destroyed in 1614 by the armies of Tokugawa Ieyasu (the founder of the Tokugawa shogunate). Ieyasu had the castle rebuilt – using the latest advancements to create terrifically imposing walls of enormous stones. The largest stones are estimated to weigh over a 100 tonnes; some are engraved with the crests of feudal lords.
There are 13 structures, including several turrets, that remain from this 17th-century reconstruction. Osaka citizens raised money themselves to rebuild the main keep; in 1931 the new tower was revealed, with glittering gold-leaf tigers stalking the eaves.
At night the castle is lit with floodlights (and looks like a ghostly structure hovering above ground). Visit the lawns on a warm weekend and you might catch local musicians staging casual shows. The castle and park are at their colourful best (and most crowded) in the cherry-blossom and autumn-foliage seasons.