Guide
How to play One Line Earth
One Line Earth is a free geography game played on an interactive globe in your web browser. Draw one straight line across the real world and cross as many countries as you can, then find countries, estimate distances and explore the atlas. There is no account and nothing to install.
Play today’s Daily LineExplore the globe
Quick start
- Drag the globe to turn it. Tap (or click) to place your first point, the start of your line.
- Tap again to place the end point. The game draws the shortest route between the two points across the globe’s surface.
- Keep the line within the distance budget, then lock it in. Every country and territory the line touches counts once, and they are revealed one by one along the route.
One Line: Daily Line, Practice and Beat My Line
The line is a great-circle route: the shortest path between two points on a sphere, which is the straight line of a globe. On a flat map it often looks curved. The question is always the same: how many countries can one straight line cross?
Daily Line
- One shared puzzle per day for every player. A new one starts at 00:00 UTC.
- Your line must start inside a given country, and the whole line must fit within that day’s distance limit (between 2,000 and 6,000 km).
- Each puzzle has a target: the best line our offline search found for that day. It is labelled “best known” because it is not a proven maximum, so you can try to beat it.
- Retries are allowed, and your best score for the day is kept on your device.
- With both points placed, another tap moves the nearer end. The start can only move within the start country.
Practice
Practice gives you a free 5,000 km line with no start country, as many times as you like. It is the place to learn which regions pack the most borders into a short distance.
Beat My Line
After a Daily Line or a Practice line, “Beat my line” shares a challenge link. Your friend plays the same puzzle and sees their score against yours: you beat them, a tie, close, or they won. The link holds only the puzzle, your score and an optional name, never your route, so it cannot give the answer away.
What counts as crossing a country
- Every country or territory the line touches counts once, including a touch on a border.
- Separately mapped territories count on their own. Antarctica can be crossed but never counts.
- Very small islands and microstates can be missing at the map’s scale. See Geography & data for exactly how the map and the counting work.
- Continents, oceans, seas and major islands along your line are listed under your score as discoveries. They never change the score.
Country Quest
Find five named countries on the globe, with three attempts each.
| Found on | Points |
|---|---|
| First try | 1,000 |
| Second try | 600 |
| Third try | 300 |
Wrong guesses unlock clues: the country’s region and its capital. Tapping the ocean costs no attempt. When a round ends, the answer is highlighted on the globe. The best possible score is 5,000. The daily set is the same for everyone; Practice makes a new set each time.
Distance Duel
Estimate the shortest surface distance between two cities, five pairs per game, with the slider or by typing a number. After each estimate the real distance and your error are shown.
Each round scores up to 5,000 points, falling off with your percentage error: 5000 × e−4 × error, rounded, where the error is the difference divided by the real distance. An estimate 10% out scores 3,352; one 25% out scores 1,839. The best possible game is 25,000.
Explore Earth
Explore Earth is an interactive atlas with no score. Tap the globe to see what is there:
- Land opens its country or territory: capital, area, continent, UN region, land neighbours and a sourced “Did you know?” fact, with links to read more.
- Water opens the sea or ocean: its category, sourced average and greatest depths, and a key feature. The Atlantic and Pacific are split at the equator into north and south.
- Continents and major islands are one tap away from any country on them, and Antarctica can be tapped directly.
You can also search for any country by name. Open Explore Earth
Controls and accessibility
- Touch or mouse: drag to rotate, tap to place or select, and use the + and − buttons to zoom.
- Keyboard: focus the globe, turn it with the arrow keys, press Enter to place a point at the centre, and zoom with + and −.
- Points can also be placed by typing coordinates.
- The game respects your device’s reduced-motion setting.
Progress, sharing and privacy
Games, personal bests, streaks and the places you have visited are saved in your browser on this device. There are no accounts and no online leaderboard. Sharing a result uses your phone’s share sheet, or copies the result to the clipboard on a computer. Shared Daily Line results include the puzzle number, your score, the target, the distance and the start country, but never your route.
Common questions
Is One Line Earth free?
Yes. Every mode is free to play in a web browser, with no account.
When does the Daily Line change?
At 00:00 UTC, the same moment for everyone, wherever you are.
Can I beat the target?
Possibly. The target is the best line found by several computer searches, not a proven maximum.
Why does my line look curved?
Because it is straight on a sphere. The shortest route between two places on Earth follows a great circle, which bends on flat maps.