Wow. It's not often one gets to witness a pod of dolphins numbering in the thousands! This "super-pod" of dolphins was spotted off the coast of California. According to the Telegraph, "Captain Joe Dutra of Hornblower Cruises told local media that the boat tour followed the pod for more than an hour."
And according to NBC Bay Area, "[Dutra] said the pod was more than 7 miles long and 5 miles wide. Guests aboard the boat started screaming and pointing when they first saw the school of adult and juvenile common dolphins. Dutra estimated there were about 100,000 dolphins swimming in the area."
It is an event that happened once last January off of Dana Point, California, as well as once around the same time and place the year before, which means it could be a migratory pattern, with many pods of dolphins coming together based on an abundance of food.