This article presents the Distributed Interactive Virtual Environment (DIVE) system, a software architecture for the realization and implementation of wide-area Internet-based multi-user virtual environments. Over the years, DIVE has evolved into a generic tool that supports a wide range of applications and situations. The article focuses on the networking aspects that allow deployment of multi-user virtual environments on the Internet. Additionally, it presents the palette of programming interfaces and techniques offered by the system. This is highlighted by some example applications. Our experience has proven that DIVE's ability to mix interfaces has made it a system of choice for the implementation of distributed applications.