Beyond traditional telecom providers, citizens and organizations pool their own resources and coordinate in order to build local network infrastructures to address the digital divide in many parts of the world. These crowdsourced network infrastructures can be self-organized and shared by a community for the collective benefit of its members. Several of these networks have developed open, free, and neutral agreements, and are governed as a common-pool resource: Community networks. These are built using a variety of commodity wireless hardware (e.g. Wi-Fi long range point to point links, Wi-Fi and GSM access points, and mesh networks), sometimes optical fibre links, heterogeneous nodes, routing protocols and applications. A group of researchers, developers and community networks developed the Community-Lab testbed, and for the last five years have worked together to overcome obstacles, improve the technologies, tools and operational models being used, as well as model best practices for more effective and sustainable community networks. This article presents the challenges for experimentation, the testbeds built, results, lessons learned and the impact of that work to place wireless community networks as one sustainable way towards an Internet accessible to All.