Offi­cial­ly the Basil­i­ca de la Sagra­da Famil­ia, this famous­ly opu­lent church in Barcelona is the brain­child of the renowned Cata­lan archi­tect Antoni Gau­di. With work start­ing on the church back in 1882, 137 years lat­er, the Sagra­da still remains unfin­ished. It is expect­ed that the build­ing will be com­plet­ed in 2026.