Finished Puzzle Size: 16 x 20 in. Mammoth Cave National Park by Bruce Martin Located in south-central Kentucky, Mammoth Cave is the longest known cave system in the world. More than 426 miles of passages have been mapped. New areas continue to be discovered each year. This painting shows a romanticized view of kayakers navigating past giant stalagmites and stalactites as they exit the cave to one of the many waterfalls found inside and outside the cavern. Mammoth Cave is part of our National Parks Collection. Boardwalk traditional puzzles are proudly manufactured in the U.S.A. from domestic and imported materials. Our jigsaw puzzles are made with premium Eska® puzzle blue board produced from 100% recovered paper. Each puzzle comes in a collectable box with magnet close, includes a full-color reference poster, and contains resealable bag for puzzle storage. Boardwalk traditional puzzles are precision cut to fit tightly and “snap” together.