We investigate and develop energy-efficient strategies for deployment of wireless sensor networks (WSN) for the purpose of monitoring some phenomenon of interest in a coverage region. We first describe a two-level WSN structure where the sensors in the lower level monitor their surrounding environment and the micro-servers in the top level provide connectivity between the sensors and a base station. We then formulate and solve the problem of assigning positions and initial energy levels to the micro-servers and concurrently partitioning the sensors into clusters assigned to individual micro-servers so as maximize the monitoring lifetime of the two-level WSN subject to a total energy budget. This problem, called MDEA, is solved for both collinear deployment and planar deployment situations. Our experimental results show that the design and deployment of such a two-level WSN increase the network lifetime by a factor of two or more compared to a flat WSN with the same total initial energy and quality of monitoring.