Utterly surreal and irresistibly Texan, this chrome-era postcard from Aquarena Springs in San Marcos, Texas plunges viewers into the world's only submarine theatre for a Christmas special: Santa Claus makes an "unusual appearance" in the glowing, teal-lit "Under Water Living Room," greeted by aquamaids clad in nightgowns beneath the shimmering surface, a Christmas tree adorned with lights swaying gently in the current beside them. The whole tableau is bathed in an eerie green-cyan glow that makes it look like a fever dream directed by an eccentric holiday impresario — because, in essence, that's exactly what it was. Aquarena Springs, built around the crystal-clear San Marcos River springs, was one of Texas's most beloved mid-century roadside attractions, featuring Ralph the Swimming Pig and these elaborate underwater theatrical productions seen through submarine portholes by tourists in glass-bottomed boats. The card is unused and in clean condition.