Well the Chosun Ilbo has the answer and the locations of these pricey homes shouldn’t be too surprising to people familiar with Korea:

Traum Haus 5 in Seoul's Seocho-dong

Traum Haus 5 in Seoul’s Seocho-dong has been identified as the most expensive condominium in Korea for the second year running. The posted price of a unit measuring 273.6 sq. m is about W5 billion (US$1=W1,072), the same as last year and the highest price of all communal housing including apartments and condominiums.

Traum Haus 5 is a condo of 18 units spread over three four-story buildings, with a 50 m alley to the entrance and only one entrance and exit to ensure security. It has an underground bunker with a capacity of up to 200 people built to resist an earthquake measuring seven or above on the Richter Scale.

Most of the residents are chairmen of big corporations or heads small and medium-sized businesses. Samsung Group chairman Lee Kun-hee and STX Group chairman Kang Duk-soo have a unit each, and Choi Jae-won, CEO of SK Holdings, bought one in 2002. One unit remains unsold.

The other nine in the top 10 most expensive communal housing structures in Korea are all in Gangnam, the affluent part of Seoul south of the Han River. I-Park in Samseong-dong comes second but is the country’s most expensive apartment complex with a posted price of a unit measuring 269.4 sq. m of W4.47 billion.

Lee Kun-hee’s home in Itaewon in central Seoul was once again the most expensive individual house in Korea. The price is estimated at W9.77 billion, up 2.6 percent from last year.  [Chosun Ilbo]