The last time Brood X emerged from the ground was 2004. In that year there were no modern smart phones, George W. Bush was elected for his second term, Facebook was invented and Chief Meteorologist Joe Murgo was in his third year at WTAJ. One of his assignments was covering the cicadas. Take a look at the coverage from back then.
When the cicadas emerged, they came out for 3 to 4 weeks to mate, lay eggs and die. The new nymphs have worked their way back down into the ground have been tunneling and eating sap from trees from their roots. After 17 years, they have now emerged, are starting to do their mating calls, and will be out until July. At this time, the emerged cicadas life will end. The eggs will hatch, and the process starts all over again. These new nymphs will be underground until the year 2038! Imagine what the world will be like then.