In April 2025, Beijing hosted the world's first humanoid robot half-marathon. Twenty-one bipedal robots lined up alongside 12,000 human runners for a 21-kilometre race. The robots had sensors, batteries, and months of engineering behind them. The humans had legs and a decent breakfast.

It did not go well for the robots.

Almost every robot fell over at some point. One collapsed at the starting line and lay there for minutes. Another slammed into a barrier and took its handler down with it. One robot's head popped off mid-stride and rolled across the track. Engineers sprinted alongside their machines carrying spare batteries, cans of coolant spray, and rolls of duct tape — yes, actual duct tape — to hold limbs and heads back on.

Out of 21 robots, only six finished. The winner, Tiangong Ultra, crossed the line in 2 hours and 40 minutes. The fastest human finished in 1 hour and 2 minutes. Humans: 1. Robots: still learning.

A few months later, the World Humanoid Robot Games took it further — robots sprinting, playing football, doing hurdles, and kickboxing. More falling. More heads flying off. More engineers looking stressed. It's genuinely funny, and it teaches you something important: getting a robot to move reliably is *hard*.

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- **Input-Process-Output in action** — each robot uses sensors (cameras, gyroscopes, GPS) to read the world around it, processes that data to decide what to do, then sends signals to its motors. When a robot stumbles, you're watching that loop fail in real time.

- **Debugging under pressure** — notice the engineers running alongside with laptops and spare parts. That's live debugging, the same skill you practise when your Sphero veers off course and you have to figure out why.

- **Iteration and design** — the robots that finished had teams who tested, failed, and rebuilt over months. That cycle of try-fail-improve is exactly what you do when programming Sphero or Ozobot.

- **Why balance is so hard** — your brain processes thousands of tiny adjustments every second to keep you upright. Robots have to do all of that with code and sensors. Next time you program a Micro:bit accelerometer, remember: even billion-dollar robots can't walk as well as you can.

- **Teamwork matters** — every robot had a support crew of 2-3 people. Good robotics is never one person alone.

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After watching the videos, imagine you're building a robot to run a marathon. **What three features would YOUR robot need most?**

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