22Jun20118:00am, EDTMarek Zakrzewski / EPAPeople launch Chinese lanterns on Kupala Night in Poznan, Poland, late on June 21. Kupala Night is a celebration of the shortest night of the year that is marked in Poland, Russia, Belarus and Ukraine.Poles celebrate the shortest night of the yearRelated content: Solstice images on PhotoBlog Summer solstice starts with sizzling solar storm Slideshow: Solstice brings the start of summer