Hydrostatic bubble

Hydrostatic bubbles were underwater structures built by the Gungans of Naboo. The walls of those jewel-like bubbles were made of hydrostatic field membranes created by generators underneath that were capable of keeping water out while still allowing individual to pass through at certain portal zones. The city of Otoh Gunga, located beneath the surface of Lake Paonga, appeared as a glittering cluster of such bubbles.

Text and facts from the “Hydrostatic bubble” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.