Head to this historic basilica, built between 1737 and 1759, for a blinding display of opulent baroque decor. Barely a square inch of its interior lacks embellishment, most of it in gleaming gold and silver. Frescos by Diego Sánchez Sarabia and the Neapolitan painter Corrado Giaquinto adorn the ceilings and side chapels, while up above, the basilica's dome soars to a height of 50m. The highlight, however, is the extraordinary gold altarpiece in the Capilla Mayor (main chapel).
Once you've taken in the head-spinning details, search out a staff member to accompany you up the stairs behind the altar to where St John of God's remains are set deep in a niche surrounded by gold, gold and yet more gold.