This manicured site offers a thoroughly genteel castle experience. Stroll past old draw wells and boulevards shaded by chestnut trees to reach the castle (which gleams white, despite the red stone of its name) and check out neoclassical statues and fountains in the main courtyard. To see the stately period-furnished rooms inside, join a guided tour. Tours in Slovak tend to be hourly, and there's usually one or two English-language tours (check online before visiting).
A castle has stood here since the mid-13th century, but the complex seen today is a 16th-century construction. The Hungarian aristocratic Pálffy dynasty lived here until the mid-20th century.
The grounds and courtyard are free, if you don’t want to commit to a guided tour of the interior. The standard tour takes an hour; for a couple of euros more there's a longer route including the cellars (75 minutes).
Two buses each hour connect Častá, the village below the castle, with Bratislava (€2, 1¼ hours).