It’s been 25 years since Tim Berners-Lee published his plan for the world wide web.

It’s safe to say the web succeeded far beyond his original ambition to create a system for linking academic documents together. That’s largely because Berners-Lee’s employer, CERN, announced to the world in 1993 that the web would be open for anyone to use and build upon, royalty free, forever.

But Berners-Lee believes the open web is under constant threat from the governments and corporations that want to control the internet. And to fight back, he’s calling for the creation of a kind of constitution for the internet. “On the 25th birthday of the web, I ask you to join in—to help us imagine and build the future standards for the web, and to press for every country to develop a digital bill of rights to advance a free and open web for everyone,” he wrote in a blog post for Google today.

This call to arms is a welcome one. The threats to the web’s future are myriad and varied. Last year, former National Security Contractor Edward Snowden revealed that the U.S. and British governments conduct internet surveillance at a massive scale. This year, a U.S. court struck down the Federal Communication Commission’s network neutrality rules. In China, the government still seeks to control internet access with its Great Firewall. And in places like Egypt, we’ve seen governments shut down the internet on occasions in an effort to prevent activists from spreading information and organizing protests.

Berners-Lee’s proposal is part of a larger campaign, called Web at 25, that seeks to raise awareness of internet surveillance, the need for net neutrality, and the fact that nearly two-thirds of the world’s population who don’t yet have internet access. And others are thinking along similar lines. A separate campaign, called the Web We Want, is working on its own international bill of internet rights.

Ultimately, these efforts must be underpinned by more pointed technical and political work, and the good news is that this sort of thing is already underway. Many are already hard at work at technical solutions to surveillance, corporate control, and access restrictions. Coders loosely associated with the Indie Web movement are building tools like Mailpile and Twister and the messaging system BitMessage.

Some are even building new programming languages to build such systems. Others still are building decentralized wireless networks outside the control of governments and telcos. Though threats to its future everywhere, there’s good reason to believe the free and open web will live on.