If you can face the early start, this is a must-do when you're on holiday in Mahon. Es Castell is the most easterly town in Menorca and the first place in the whole of Spain to see the sun each morning. It's at the mouth of Mahon Harbour so it will only take you about 15 minutes to get there by car or taxi. Head to the seafront to see the sunrise over the Mediterranean, then spend the morning exploring this old British garrison town. One of the best places to visit while you're there is Castillo de San Felipe, so it's worth timing your trip to Es Castell to make sure you can join one of the guided tours. They're the only way to see this ruined castle and its underground tunnels, and are available at limited times. The castle isn't the town's only landmark. Make your way to Plaza de S'Esplanada square and you'll get to see the bright red town hall with its English clock tower. It overlooks the old parade ground that's now at the heart of daily life in Es Castell. While you're there, you could pop into the Menorca Military Museum or browse the weekly market. And if you're more of a night owl than an early riser, the restaurants that line Cales Fonts (one of Es Castell's two natural harbours) make it an equally special place to spend the evening instead.