Interactive terrain visualization is useful for various applications such as Geographical Information Systems, military training, city planning and tourist information systems. In most of these cases, it is natural to use a Client-Server architecture, in which the data, usually very large, is stored in one or more servers, that respond to requests made by client programs running on the users'  machines. This work addresses the various techniques -- data storage schemes, network communication, data visualization and interaction control -- imployed in such systems. Based on this discussion, an application to allow visualization of large terrain data over a local network was developed. This system adopts a multi-resolution representation for the terrain data. This allows fast interaction between user and application, regardless of the size of the data, due to the use of algorithms which select the appropriate level of detail for rendering the scene. System implementation issues are discussed in detail, and performance is assessed.