. >> mass encars ration, rainfall p racial profiling resonate with visitors today. >> reporter: nearly 43,000 people have viewed the exhibit since it opened, roughly a year ago, outstripping other exhibits. it's so popular that it's now being renewed. >> for an entire additional year through 2019. >> carrying mlessons of the pas into the present. >> something special is happening in the sky tonight and in the early hours of tomorrow morning. abc7 news reporter jonathan bloom explains why once in a blue moon doesn't even begin to explain tonight's celestial experience. >> we have a super blue blood moon. >> it that hasibilin't happened 150 years. something that nobody alive has seen. >> first there's the supermoon. >> we have a full moon that appears brighter because the moon is about 7% closer. >> reporter: it's the second one this month, and that's called a blue moon ch. >> what's a blue moon? >> it's when the moon turns blue. >> reporter: well, actually not. the earth's atmosphere scatters the sunlight and turns the moon the color of blood. >> so a super blue blood moon. >> our moon