How do hackers, viruses, malware and other computer nasties work? How can you make your computer safer? In issue 136 of How It Works, we’ll be exploring the dark side of the internet as we speak to a genuine hacker about the US military website he seized control of and how today, he uses his hacking skills for good. Also this issue: become a back garden eco-warrior, inside the Bank of England’s vaults, which is worse: smoking or vaping?, 250mph next-gen super trains, and much more.