Abstract: A one-atmosphere underwater modular system is provided. The modular system comprises components which can be manipulated and attached to one another through use of a submarine or the like. A variety of components are provided including: a maneuvarable submarine component; a bottom frame; a two-connection module; a one-connection module; and christmas tree modules. A variety of means and methods for connection in various orientations is disclosed. The system is specifically adapted for use in the recovery of natural resources, such as for oil and gas recovery.