Have you ever seen a horizon rainbow before? This fascinating phenomenon was recently captured by photographer Bertrand Kulik in Paris, France. According to Robert Nemiroff and Jerry Bonnell of NASA’s Astronomy Picture of the Day (APOD):

“What is pictured above is actually just a common rainbow. It’s uncommon appearance is caused by the Sun being unusually high in the sky during the rainbow’s creation. Since every rainbow’s center must be exactly opposite the Sun, a high Sun reflecting off of a distant rain will produce a low rainbow where only the very top is visible — because the rest of the rainbow is below the horizon.
 
Furthermore, no two observers can see exactly the same rainbow — every person finds themselves exactly between the Sun and rainbow’s center, and every observer sees the colorful circular band precisely 42 degrees from rainbow’s center.” [Source]