Network virtualization enables the coexistence of multiple networks, running different protocols, in an infrastructure-independent way. With that goal in mind, this paper presents a Platform for Operator-driven Network Virtualization that builds virtual networks through a user-friendly interface, integrating virtual network mapping and creation, discovery, monitoring, and management functionalities. Besides the developed functionalities, this platform contains novel mechanisms for network discovery and mapping: a novel dynamic distributed discovery algorithm of both physical and virtual nodes, and a heuristic algorithm for mapping virtual resources in the physical infrastructure, that supports the heterogeneity of networks, with respect to both links and nodes. The platform and its features were implemented and evaluated in different scenarios. The obtained results show the scalability and feasibility of the proposed mechanisms and functionalities in a single platform for network virtualization control and management.