We've all seen the big 6-volt lantern battery, and I use a few of them every year, mainly to power my deer feeders. Several months ago Milady came home with an urban legend that a lantern battery is filled with AA batteries. I went to Snopes and debunked it. Then told her to tell her buddies that they were full of crap.
Today after lunch, I had the grandkids helping me put a new motor on a feeder and my son determined to disassemble an old dead lantern battery. He'd heard the legend too, and decided to disassemble a standard Duracell lantern battery to find out what's inside it. What do you think? D-cell batteries. Four of them. No kidding.