"The cathedral anchoring St. Mark's square is so over-the-top beautiful it almost looks imaginary, like a church in a storybook. Outside, it's all Byzantine domes and columns and lions and angels; inside, it's aglow with glittering, gilded mosaics. For those just interested in the architecture, you can visit when there's not a mass in session (it's still very much a functioning church, with regular services), but check the website for the latest on the sometimes-nonsensical opening hours. Also know that, because it's in the Times Square of Venice, the church has had to start limiting crowds in recent years and there's often a long line. Make plans to go early." - Andrea Whittle
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