Driven by a massive surge in digitization and customization, so-called vertical industries are expected to be a major beneficiary of the 5G of mobile networks. The use cases of such vertical industries define qualitative and quantitative requirements unprecedented in the history of mobile network development. Autonomous vehicles, traffic light control, video surveillance, and IIoT, to only name a few, introduce challenging requirements regarding both conventional performance metrics, such as throughput and coverage, as well as formerly rather subordinate system metrics, such as deterministic latency, ultra-high reliability and resilience, high number of devices, multi-tenant networks, and demanding security mechanisms. Nokia, Deutsche Telekom, and Hamburg Port Authority have deployed a largescale 5G trial testbed in the Hamburg port area. The testbed proves in a real, large-scale industrial environment that basic features of network slicing, namely slice isolation, flexible slice customization, and multitenancy, are already technically feasible. Three exemplary communication services have been selected and are demonstrated in the testbed. Multi-connectivity is implemented as a key component to achieve high reliability throughout the testbed area. The testbed shows that all network domains must be involved in the setup of network slices, that is, user terminals, radio access, core network, and enterprise networks, in order to efficiently operate and manage network slices. Therefore, the discussed life cycle management is key for the interaction between mobile service provider and tenants of the network.