This paper describes Project GIGA - High-speed Experimental Network, a multi-institutional, multidisciplinary, national project funded by the Brazilian government. The main goal of Project GIGA is to promote research, development and experimentation of technology at all layers, aiming at generating knowledge, products and services that will make it possible for Brazilian individuals and companies to play a role in the converged telecom sector. The project centres on the High-speed Network Testbed, a platform for experimentation and validation of technology, equipment, protocols, services and applications, whether they be developed in the project or not. The paper explains the objectives, the expected impact and the organisation of the project. It also describes the architecture of the network testbed, the ongoing research and development activities and some of the results obtained.