This paper describes the architecture implemented in five different countries to vaIidate, by means of tests carried out with expert users, a service architecture for the interactive retrieval of multimedia information. The service architecture definition (which corresponds to the DAVIC 1.0 Specifications) and all activities for the set-up and running of the experiments, have been carried out within the RACE R2120 "Multimedia Audiovisual Retrieval Services" (MARS) project. A unique server and terminal architecture has been developed and put in opention at each site, while a combination of different public network solutions were used for the terminal access side. All national experiments made use of an ATM-based transport network. The interconnections between the five countries were provided by the European ATM Pilot (EM). The minimal testbed configuration implemented in each country consisted of one server and two terminals. After the integration and test phases, this configuration was extensively tested within the national environment to obtain the users' perception of the service.