Devin Castle is just a few miles from Bratislava and easily accessible by Uber, local bus and I think even boat. Stroll among the ruins of one of the oldest castles in Slovakia and make sure to get a good picture of minuscule Maiden Castle, perched precariously on a tiny rock somewhat separated from the rest of the site. There are numerous, probably apocryphal, tales about distressed lovers flinging themselves from its turrets. Don’t forget to stop by the adjacent memorial honoring those who lost their lives trying to cross the Danube here during the Cold War, it’s heartbreaking.