i started by going to home depot and got some pvc pipes and some elbows. then figured out how i wanted to set them up... this is what i started with:
http/pic16.picturetrail.com/VOL660/27786...45/71471356.jpg
after finishing that piece i wanted to make some more so i did:
http/pic16.picturetrail.com/VOL660/27786...45/71981500.jpg
then i figured i could block of the elbow pieces to divide them to make more cave:
http/pic16.picturetrail.com/VOL660/27786...45/71981505.jpg
http/pic16.picturetrail.com/VOL660/27786...45/71981516.jpg
then i covered it with sand and added some plastic plants:
http/pic16.picturetrail.com/VOL660/27786...45/72182132.jpg
thats all
http/pic16.picturetrail.com/VOL660/27786...45/71471356.jpg
after finishing that piece i wanted to make some more so i did:
http/pic16.picturetrail.com/VOL660/27786...45/71981500.jpg
then i figured i could block of the elbow pieces to divide them to make more cave:
http/pic16.picturetrail.com/VOL660/27786...45/71981505.jpg
http/pic16.picturetrail.com/VOL660/27786...45/71981516.jpg
then i covered it with sand and added some plastic plants:
http/pic16.picturetrail.com/VOL660/27786...45/72182132.jpg
thats all