The Citadel of Alba Iulia is a star-shaped fortress located in Alba Iulia, Romania. Built in the 18th century, it was designed by the Italian architect Giovanni Morando Visconti and served as a military stronghold. The citadel features impressive walls, bastions, and gates, showcasing the Vauban style of fortification. Today, the citadel is a significant historical site, attracting visitors with its well-preserved architecture and rich history. Inside, you can find the Union Hall, where the union of Transylvania and Romania was proclaimed in 1918, as well as various museums and cultural events.