Soaring above Barcelona’s cityscape, the Sagrada Família will be the world’s tallest church upon completion (estimated, finally, for 2026). This 130-year labour of love, dreamt up by Antoni Gaudí, is one of the world’s most controversial basilicas, but also one of the most visited. Three million tourists flock here each year to gawk at the architectural achievement that has brought nature, light and religion together into one stunning ensemble. The interior is like a giant jigsaw puzzle, with each new style blending into the rest of Gaudí’s visionary design.