Marine Tube

Known as "the walk-through aquarium", the Marine Tube was built during the two years between Pokémon Black and White and their sequels. It was constructed to commemorate the friendship between Undella Town and Humilau City and was designed, as stated by an NPC, "to see, not to move." When the player first arrives in Undella Town, the Marine Tube is closed for cleaning and yet to open. The cleaning is completed at the same time the player earns the Legend Badge and defeats Team Plasma in Opelucid City. The Marine Tube is a transparent tube made of 9.8 inch glass built to withstand high water pressures and contact with huge Pokémon. The tunnel was made above ground and lowered into the water.