The Medium Sea cave; dimensions 6.5" long x 4" wide x 3 " tall, is like the Large Sea Cave, styled after sandstone sea cliffs erroded by the surf. It has 3 openings including the main ground level opening you see in the primary photo. The secondary photo is a top view and shows the large opening in the back as well. The main opening at ground level is at the northern most side of the cave in the photo. Great for creating hiding and exploring space for more harmony in any community tank!