Barcelona

The Temple de la Sagrada Familia, designed by Antoni Gaudi, and still under construction after more than 100 years of work. (To be fair, progress was given a hefty setback during the Spanish Civil War due to rioters damaging the building and destroying many of the original plans.) Most likely one of the least conventional cathedrals in the world, even more evident when up close than from afar.

One of the tamer parts of Parc Guell, another Gaudi-designed construction. Originally designed as a neighborhood/microcosm for the wealthy, it was converted into a park after almost no one signed up to actually live there. Atop a fairly significant hill, it commands a fine view of Barcelona.