Ordered built by none other than Tsar Nicholas II, Russia’s last emperor, this recently renovated cathedral is the most beautiful religious edifice of the Orthodoxy outside Russia. It dates from the Belle Epoque, when some of the Romanovs and entourage turned the Riviera into their stomping ground. Everyone from grand dukes to ballerinas arrived on the reinstated direct train from Moscow (it takes two days, crosses eight countries, and costs from 300€ one way), then paraded their tiaras on the promenade. The cathedral is richly ornamented and decorated with icons. You’ll spot the building from afar because of its collection of ornate onion-shaped domes.