You may not have heard of Crawford Lake in Canada… because at first glance, it’s really just a sinkhole. But for those in the know, this little body of water holds the key to understanding humanity’s impact on the planet: from hydrogen bomb tests to the use of fossil fuels. In today’s deep dive, TDA’s deputy editor Emma Gillespie is going to share with us what secrets have been discovered so far and what it all means for humanity.