On an island across the Chao Phraya River from Bang Pa In Palace, this unique buttercup-yellow ubosot (ordination hall) was designed to resemble a European Gothic cathedral. And since its spire holds a Buddha relic, it's actually a one-of-a-kind stupa. Inside you can admire stained-glass windows and gilded filigree that wouldn't look out of place in a European church.
Take a free, monk-operated cable car across the river from the palace parking lot (leave a donation in the boxes).