A British company named Deep is advancing its plans to establish permanent human settlements below the ocean's surface. 

Backed by an anonymous investor (let's have some fun and try to guess who it is!), Deep is developing "sentinels"—house-sized, mobile underwater habitats designed to operate at depths of around 80 meters (260 feet). 

These housing units will provide scientists and researchers with extended access to marine environments, enabling prolonged study of the oceans and their ecosystems. 

Of course, the initiative also has an element set to attract eco-tourists interested in fully-immersive underwater experiences. We've seen expeditions to explore the underwater world for centuries, some with success and some ending tragically. Creating safe, sustainable, habitats is the primary goal. 

_{Image credit: Deep (https://www.deep.com/sentinel)}