Tutorial
Six steps, the same six printed on the back of the postcard — just with more room to explain them. If you've got a card in your hand, you already have everything you need.
- 01
Choose your mission
Scan the mission code on the front of your postcard, or browse the walks we've mapped. You'll get the whole route on a map — every stop, the total distance, and roughly how long it takes on foot — before you commit to anything.
Tap Walk this mission to switch it on for your phone. That's what lets the GO code recognise you later, so do it before you set out.
Browse missions → - 02
Walk to the Sun
Every mission starts at a Sun — a fountain, a sculpture, a dome, something real you can stand next to. Its actual physical size sets the scale for the entire walk, so this is the one stop you can't skip.
We'll hand you off to Google or Apple Maps to get there, on foot or by transit. Nothing else on the walk makes sense until you've stood at the Sun.
- 03
Scan the GO code
GO is the only code you really need. Scan it and it works out where you are in the walk: at the Sun it starts you off, en route it points you at your next stop, and at a stop it brings up the planet.
One code, every situation. You never have to pick a planet from a list — your location and your progress decide what happens.
- 04
Scan the AR code at the planet
You've arrived. Scan the AR code, then point your camera at the printed border — the wallet card's frame or the back of the postcard. The planet appears at true scale against the real street behind it.
Hold whichever piece you like; the app measures against the one in frame, so the size is right either way. If tracking wobbles, the planet stays put on screen until you line the border back up.
- 05
Enjoy the planet
Stop and smell the (local) roses. Get the photo — with friends, with the planet, with whatever's behind you. This is the part people remember, and it's the reason the stops are at real places rather than empty corners.
Missed the shot? Scan the AR code again any time. It brings back the planet for the stop you're standing at.
- 06
Scan the GO code again
When you've had enough of that planet, scan GO again and it hands you the next waypoint. Repeat all the way out. Neptune may genuinely be kilometres away — that gap is the whole point, and it's the thing you'll be telling people about afterwards.
Going far? Download the mission's waypoints into Google Maps from the mission page and plan a transit hop. Riding part of it is completely fine.
Plan my own walk →
Two more codes, for when things go sideways
Lost?
The card calls this the reset code, and a full reset is still there — but it's at the bottom, behind a confirmation, because "lost" almost never means "erase four hours of walking". What you get first is help: where your next stop is, a way to say I'm here when GPS disagrees with you, and the option to skip a stop you can't reach.
Open the help page →Going far?
At true scale the outer planets are a real journey. Every mission page has a download that loads the waypoints straight into Google Maps, so you can plan transit between the far stops. Taking the bus to Neptune isn't cheating — the distance is real either way.
Find a mission →Things people ask
Do I need an account, or an app?
Neither. It runs in your phone's browser, and your progress is saved on the device itself — nothing is sent to a server, nothing to sign up for.
Does one card really work everywhere?
Yes, forever. The card carries no city and no planet — where you are and how far along you are decide what appears. Take the same card to a different city and it just works.
GPS says I'm not at the stop, but I am.
Believe yourself, not the satellites — in a city they're routinely tens of metres out. Every screen that mentions a stop has an I'm here button, and tapping it credits the stop and brings up the planet.
I can't make it all the way to Neptune.
Then skip it. You'll get an honest finish — "6 of 8 found, 2 skipped" — and the stops you skipped stay open if you ever double back. A partial walk is still a walk.
Why is Neptune so far away?
Because that's genuinely how far Neptune is, at the scale of the Sun you're standing next to. We never shrink the gaps to make a route tidier. Feeling that distance in your legs is the entire idea.
There's no mission in my city.
Build one. Pick a landmark for the Sun and the planner works out where every planet lands at that scale. Keep it to your own phone, share it with friends, or submit it to go live for everyone.