The present invention relates to a system and method for constructing a pre-stressed modular construction for supporting or retaining an applied load. In particular, the present invention relates to a system and method for pre-stressed modular retaining walls. The system comprises a plurality of header stacks constructed from a variety of header units. The header stacks are coupled by structural members. Active reinforcement elements are used to induce a pre-stressing force into the header stacks to support or retain the applied load. A method for constructing the modular construction is provided.