Sagrada Familia

Since 1882 a cathedral in Barcelona known as the Basílica i Temple Expiatori de la Sagrada Família (which translates roughly into "Basilica and Expiatory Temple of the Holy Family") has been under construction, aside from a two-decade-long interlude between the Spanish Civil War and the 1950s. Designed by Antoni Gaudi and expressing Gothic and Art Nouveau architectural styles, the cathedral is a UNESCO heritage site, though its estimated completion date remains more than a decade away. You can read more about it here:
Sagrada Familia

The reader is encouraged to look through Wikipedia's gallery. Like an architectural counterpart to The Beatles' "Tomorrow Never Knows," the Sagrada Familia is at once sublimely beautiful and offensive to the senses. "Ornate" is the best word that comes to mind to describe the cathedral, but seems too limited in scope to adequately capture the richly detailed Gothic design etched into the facades, spires, ceilings, and columns. Like one of the great medieval cathedrals, Sagrada Familia is so horrendously complex in design that it's been under construction for over a century and won't be finished until 2026. I won't be too surprised if the schedule slips.

I'm not sure quite what I think of the church's design. Generally I prefer elegant simplicity to baroque complexity, but it's difficult to look at the photos of construction on Sagrada Familia so far and not be struck by a sense of genius in the newness of the place. In some places, brand-new stonework sits next to 19th-Century bricks. There's something oddly alluring about a place unified in form but so diverse in provenance. Gaudi's genius took a bizarre turn, but surely the world will be richer for it when the last brick is laid in Barcelona.