With Shell’s retreat from the Arctic Ocean, we have a lot to celebrate.

Marine mammals and seabirds are out of danger from an almost-certain oil spill. Subsistence whalers and hunters who depend on a healthy ecosystem for food security need not worry about Shell’s intrusion and the massive infrastructure that would accompany it. For now, that oil will stay in the ground, which means a great deal to the planet.

We also have a lot to reflect on as we try to untangle the story that led to this truly incredible outcome. After President Obama’s withdrawal of 9.8 million acres in the Beaufort and Chukchi Seas in January 2015, the conservation community paused to celebrate this victory, and then set about working to protect additional areas, targeting those with the richest biodiversity. All the while, the looming specter of Shell’s plans to drill that summer cast a dark shadow over the maps and plans to create additional protected areas.

During the spring and into the summer, the tangled web of strategies unfolded: lawsuits, policy tweaks, grassroots organizing, celebrity actions, social media mania, and then the kayaktivists. A word that would not have shown up on a Google search a year ago, the kayaktivists served on the front-lines, creating a platform (literally), for environmentalists around the globe to rally around. And did they ever—one count put the number of activists engaged on this issue at 7 million.

Any one of these tactics alone would not have forced Shell out. And indeed, it can be argued that the low price of oil was really the driver for their decision to leave this risky and costly experiment behind. We’ll never know the exact combination of factors that led to Shell’s retreat. By encouraging the Obama Administration to stick to their commitment of strict safety standards, we succeeded in forcing Shell to consider the true cost of their operations. For this, we should most certainly celebrate.