People swim in the lighted water of the Hirschengraben indoor swimming pool in Bern during an artistic performance by Swiss visual artist Pipilotti Rist and World Wide Fund for Nature (WWF) Switzerland non-governmental organization to denounce the disappearance of corals due to the warming and the acidification of the ocean on October 7, 2018. (Photo/Agencies)
A woman swims in the lighted water of the Hirschengraben indoor swimming pool in Bern during an artistic performance by Swiss visual artist Pipilotti Rist and World Wide Fund for Nature (WWF) Switzerland non-governmental organization to denounce the disappearance of corals due to the warming and the acidification of the ocean on October 7, 2018. (Photo/Agencies)
Swiss visual artist Pipilotti Rist laughs as she poses in the lighted water of the Hirschengraben indoor swimming pool during an artistic performance and World Wide Fund for Nature (WWF) Switzerland non-governmental organization to denounce the disappearance of corals due to the warming and the acidification of the ocean on October 7, 2018. (Photo/Agencies)
People swim in the lighted water of the Hirschengraben indoor swimming pool in Bern during an artistic performance by Swiss visual artist Pipilotti Rist and World Wide Fund for Nature (WWF) Switzerland non-governmental organization to denounce the disappearance of corals due to the warming and the acidification of the ocean on October 7, 2018. (Photo/Agencies)
