One city. Five guesses. You start with temperature and population, and each wrong guess unlocks a new clue. Correct guesses win immediately; wrong guesses show distance and direction to the right answer.

1. Temperature and population. Both clues are visible from the start.
2. Elevation. Unlocks after the first wrong guess.
3. Local time. Unlocks after the second wrong guess.
4. Landscape. Unlocks after the third wrong guess.
5. Top airlines. Unlocks after the fourth wrong guess, before your last attempt.

• Hemisphere flips. If it’s 32°C in July, anywhere in the Northern Hemisphere is plausible. If it’s 32°C in January, you’re in the Southern Hemisphere or the tropics.
• Elevation is a game-ender. Above 2,500m means a specific short list: Cusco, La Paz, Lhasa, Quito, Bogota, Addis Ababa. Below 10m often means a coastal or river-mouth city.
• Temperature + elevation together is very tight. 10°C at 3,000m mid-summer narrows to Himalayan or Andean high cities immediately.
• Watch the population tier. “Over 10M” leaves you 25-30 cities globally. “Under 500K” opens up 10,000+ options — save this tier for when other clues lock it down.
• Use local time to narrow the time zone, then landscape and top airlines to distinguish nearby candidates.