The Alcázar of Seville (Spanish: Los Reales Alcázares) is among the most beautiful buildings I have seen so far. It is still the residence of the Spanish royal family when they visit Seville. Unesco declared it a World Heritage Site, next to the Cathedral and the Archive of the Indies, in 1987.
The Fontanelle Cemetery in Naples, Italy, is an ossuary, a charnel house. In the past, they were stacked in a tuff quarry the corpses of the great plague of 1656 and the 1836 cholera. In this ossuary Neapolitans spontaneously developed a real cult of the dead. People adopted and took care of the skulls hoping to receive favors.