Cittopia's lighthouse pair. Twinned since 1991 under the Polish-Turkish Treaty of Friendship. Now running shared dashboards, joint programs, and comparative metrics — the model for what city-to-city diplomacy looks like in 2026.
Twinned since 1991 · 34 years of cooperation · 5 mayors on each side
12
Active programs
47
Exchange staff
5
Open joint projects
8
Anniversaries marked
1991
Treaty year
The pair at a glance
Two cities of similar civic ambition but very different history, climate and scale. Cittopia tracks both side by side.
🇵🇱
Warszawa
Republic of Poland
Capital city · 4-year mayoral term · Phoenix city — rebuilt after WWII destruction. Cittopia administrator: Magdalena Kowalska, Urząd m.st. Warszawy.
Trans-continental metropolis · 5-year mayoral term · Only city straddling two continents. Cittopia administrator: Ayşe Demir, İstanbul Büyükşehir Belediyesi.
Selected milestones from the Warsaw–İstanbul partnership.
1991
Polish-Turkish Treaty of Friendship signed in Warsaw on March 3 by President Wałęsa & President Özal. The treaty includes a city-twinning protocol formally pairing the two capitals' commercial centres.
1996
First cultural exchange program: Warsaw National Opera tours İstanbul; Topkapı Palace exhibition tours Warsaw's Royal Castle.
2003
Joint urban-planning workshop on managing rapid growth — both cities saw 20%+ population increase in the 90s. Outputs informed both capitals' 2010–2020 strategies.
2011
20-year anniversary marked with the Polish-Turkish Friendship Park opening on Warsaw's Powiśle riverfront. Reciprocal Polish garden installed in Maçka Park, İstanbul.
2018
Reciprocal staff exchange formalised: 12 Warsaw municipal officers spend 3 months in İBB; 12 İBB officers spend 3 months at Urząd m.st. Warszawy. Annual cycle continues today.
2023
Climate cooperation pact signed: shared targets for tree-planting (1M trees each by 2030), public-transport modal share, and air-quality monitoring methodology.
2026
🚀 Both cities go live on Cittopia as the lighthouse pair. Joint dashboard, comparative Pulse, shared Sister Cities Hub. The first city pair anywhere with a published Listening Score.
Active joint programs (2026)
Currently funded, currently shipping. Visible in both cities' admin dashboards.
🌳
2M Trees by 2030
Joint commitment: 1M climate-resilient trees in each city by 2030. Shared species methodology (Quercus cerris, Tilia tomentosa).
Active
🚇
Transport benchmarking
Shared modal-share methodology, monthly figures published openly. İstanbul's BRT learnings shared with Warsaw's Tramwaje Warszawskie.
Active
🎭
Cultural seasons
Annual reciprocal cultural seasons: "Warszawa in İstanbul" each spring · "İstanbul w Warszawie" each autumn. 2026 theme: contemporary photography.
Active
🎓
Student exchange (HE)
Reciprocal scholarships: UW & SGH ↔ Boğaziçi & İTÜ. 60 students per year per direction. Languages: Polish, Turkish, English.
Active
🏛️
Historic-quarter preservation
Joint working group on UNESCO heritage management — Warsaw's Old Town & İstanbul's Sultanahmet face similar restoration challenges.
Active
🤝
Mayoral office exchange
Two senior staff from each mayor's office exchange seats for 3 months annually. Currently in cycle 8.
Active
📊
Air-quality methodology
Shared PM2.5/NO₂ monitoring + reporting methodology. Both cities publish hourly figures using identical sensor calibration.
Active
🏗️
Affordable-housing pilot
Cross-learning on social housing models. Warsaw's TBS scheme ↔ İstanbul's KİPTAŞ — quarterly study calls, annual joint report.
Planned 2026
The numbers, side by side
A handful of indicators where the comparison is immediately telling. Full per-city breakdown in each city's profile.
Indicator
🇵🇱 Warszawa
🇹🇷 İstanbul
Population (2024)
1.86M
15.84M
Population density (per km²)
3,500
3,030
Pulse score (Apr 2026)
72 🥈
61 🥉
Listening Score
71%
68%
Public-transport modal share
47%
39%
Higher-education attainment
52%
31%
Green space per capita (m²)
28
7
Sister cities (total)
25
38
Open-data portal published
✓ 2018
✓ 2020
Sister cities are how international cooperation survives the fraying of the nation-state. When Warszawa and İstanbul publish their Listening Scores side by side, a citizen in either city can see — in real time — whether their mayor is doing the work. That is what 21st-century diplomacy looks like.
— Tunç Meriç, founder of Cittopia · April 2026
Bring your sister-city pair onto Cittopia
If you administer either side of an existing twinning agreement — anywhere in the world — we'd love to host your pair. Email us with the cities and we'll talk.
