Teheranno (alternatively Teheranro, translation "Tehran Street") is a street in the Gangnam district of Seoul, South Korea. It is colloquially known as "Teheran Valley" (after Silicon Valley) due the number of internet-related companies operating there, including Yahoo!, and Korean rivals Daum and Naver. Various Korean and international financial and business institutions including POSCO, Standard Chartered and Citibank also maintain offices here. Some of Korea's tallest skyscrapers and most expensive real estate are on Teheranno, while Seoul Metropolitan Government estimates that more than half of Korea's venture capital, some 200,000,000,000 won (approximately $200,000,000), is invested in Teheran Valley.
Teheranno is a 3.5 km section of Korean Highway 90, and runs eastwards from Gangnam Station to Samseong Station and the COEX/KWTC complex. Yeoksam and Seolleung stations are also on Teheranno. All stations are on Seoul Subway Line 2.

Photo gallery
Posteel Tower, Teheranno
Yahoo! Korea Tower
POSCO Center, Teheranno
Roadsign, COEX-KWTC intersection
POSCO Center at night