Alba Iulia is one of Romania's most historically significant cities, the place where the unification of Transylvania with Romania was declared in 1918. The star-shaped Vauban fortress — the Alba Carolina Citadel — dominates the town and is one of the finest examples of Habsburg military architecture in southeastern Europe. Restored and well-maintained, the citadel is a pleasure to walk through, with baroque gates, churches, museums, and a daily changing-of-the-guard ceremony.
Inside the fortress walls you will find St. Michael's Cathedral (13th century, containing the tomb of John Hunyadi) and the Coronation Cathedral (built in 1922 for the coronation of King Ferdinand and Queen Marie), standing almost side by side — a visual summary of Transylvania's layered history. The National Museum of Unification covers the region's story from Dacian times through the Roman, Hungarian, Ottoman, and Habsburg periods. The Obelisk of Horea, Cloșca, and Crișan marks the site where three leaders of the 1784 peasant revolt were executed.
Alba Iulia sits on the main road between Sibiu and Cluj-Napoca, making it an easy stop on a Transylvanian road trip. The town itself is small and manageable — the citadel is the main attraction, and a half-day is enough to see it well.