Light Floor

Floors by City

The speed-of-light round trip between any two of 79 cities: the 60 largest in UN DESA's World Urbanization Prospects 2025, by mid-2025 population, and 19 more for the cloud regions on the home page: for each region, the largest city the UN counts within 60 km, in the same country. 3,081 pairs, each on its own page with the distance, the vacuum floor and the glass floor.

The UN draws a city as one dense, contiguous built-up area rather than by its legal boundary, so the list follows where people live: Hajipur, India, counts as one city of 9.9 million. Each city sits at the UN's population-weighted centre. Oregon's cloud region has no city here: its stand-in, Bend, is below the UN's threshold, and the nearest city the UN counts, Eugene, is 140 km away.

Open a city; each figure is the round trip at the speed of light in a vacuum.

Abidjan, CI
Addis Ababa, ET
Ahmedabad, IN
Alexandria, EG
Bandung, ID
Bangkok, TH
Beijing, CN
Bengaluru, IN
Bogotá, CO
Buenos Aires, AR
Cairo, EG
Calgary, CA
Cape Town, ZA
Chennai, IN
Chongqing, CN
Columbus, US
Dar es Salaam, TZ
Delhi, IN
Dhaka, BD
Dubai, AE
Dublin, IE
Frankfurt, DE
Guangzhou, CN
Hajipur, IN
Hangzhou, CN
Ho Chi Minh City, VN
Hong Kong, HK
Hyderabad, IN
Istanbul, TR
Jakarta, ID
Johannesburg, ZA
Karachi, PK
Khartoum, SD
Kinshasa, CD
Kolkata, IN
Kuala Lumpur, MY
Lagos, NG
Lahore, PK
Lima, PE
London, GB
Los Angeles, US
Luanda, AO
Manila, PH
Melbourne, AU
Mexico City, MX
Milan, IT
Montreal, CA
Moscow, RU
Mumbai, IN
Nagoya, JP
Nanjing, CN
New York City, US
Osaka, JP
Paris, FR
Pune, IN
Querétaro, MX
Rio de Janeiro, BR
Riyadh, SA
San Francisco, US
Santiago, CL
São Paulo, BR
Seoul, KR
Shanghai, CN
Shenzhen, CN
Singapore, SG
Stockholm, SE
Surabaya, ID
Surat, IN
Suzhou, CN
Sydney, AU
Taipei, TW
Tehran, IR
Tel Aviv, IL
Tianjin, CN
Tokyo, JP
Washington, D.C., US
Wuhan, CN
Zaragoza, ES
Zurich, CH

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