The mystery of the dark rainbow

Many years ago I saw a "dark rainbow". A perfect bow,  a dark curved band in the air, the same width and same shape as a normal rainbow. It was appearing in the south, where the dim sun also appeared, around 11:00 am. Later that day, my social network confirmed that others had seen this mysterious phenomenon as well. Mysterious indeed; nobody knew what it was or what could be the physical explanation! I contacted several meteorologists by email, but I never received an answer. All those years, none of the meteorological books that came in my hands provided a even the smallest clue... What could it have been?!!

Lego einfach reinigen

Altes Lego auf dem Dachboden? Total verstaubt und verschmutzt? Mein Versuch so was recht unkompliziert sauber zu bekommen, hat so gut funktioniert, das ich ein paar Tips gerne hier teilen möchte.