GTS is a new service in GÉANT that allows users to set up wide-area virtual networks via a web-based automatic provisioning system. The virtual networks are built within minutes over the underlying physical infrastructure and thus allow the researcher to carry out network experiments with great flexibility and enable rapid prototyping and innovation. The individual network environments are isolated from other users and are assembled following the researcher's topology requirements. Currently a researcher can select GTS virtual machines (VMs), virtual links (VCs) and OpenFlow instances (OFXs) as network resources in the virtual network, but the architecture of GTS is scalable and can be expanded anytime with new resources. A user can also connect external facilities to such automatically provisioned environments or use GTS as connecting fabric between distributed labs. This paper provides an overview of GTS and describes upcoming versions with further developments and feature improvements.