Subways are a massively popular mass transit solution. They're also expensive to build. And complicated. Just think about the problems that a city faces when it decides to build one.
Modern cities are crammed to the limit with things: high-rise buildings, malls, streets, parking lots... where do you dig? How do you pull off such a project without disturbing normal life on the surface?
To the tunnel!
It's a pretty good question, and it's one that we're answering in today's OWLconnected General KnOWLedge. From ripping up roads and parks to using a boring machine (their name, not ours!), this is one exciting topic.
So why not dig deep into the facts right now? You don't even need to get your hands dirty. Simply press play below and find out how subways are built!