The Vision of St. John The Evangelist by Alonso Cano
The Vision of St. John The Evangelist, circa 1636-7, by Alonso Cano is a beautiful, small, Spanish painting held at The Wallace Collection in London. It shows an angel revealing a vision of Heavenly Jerusalem to St. John The Evangelist.
It would appear to feature a version of King Solomon's Temple or more likely a depiction of the Dome of The Rock in the cloudy apparition above the two central figures.
Cano's painting technique ad use of color is beautiful.