When the Panama Canal locks were completed, they became the largest concrete structures in the world. The original system included 12 chambers across the three lock complexes: Gatun on the Caribbean side, and Pedro Miguel and Miraflores on the Pacific side. The side walls of each lock resembled giant staircases, with 6-foot steps. Their bases were 45 feet thick, while the top measured 8 feet wide. From the floor to the top, the walls stood 78 feet high. Inside the walls, 18-foot-diameter culverts carried the water. Beneath the chamber floors, 20 lateral culverts distributed the flow through 100 openings.