Number four, we've returned to the bottom of the ocean for the black coral. They are 4000 plus years old. Number three is the glass sponge, estimated to be 10,000 years old. Sponges are made up of colonies of animals similar to coral and can also live for thousands of years. Glass sponges are among the longest living sponges on the earth. Members of this group often are found in the deep ocean and have skeletons that resemble glass. Hence the name that according to NOAA