Seoul was opened as the first of three new cities to be made available for the popular city sieges in the seafarer's MMO Bounty Bay Online. On the following two Sundays, Barcelona and Athens will likewise be opened for guild conquest.

With these new additions, a total of 16 cities will be available for conquest. They are divided into three categories: trade cities, martial cities, and resource cities (Seoul, Barcelona, and Athens belong to the latter). These three types are available for guild conquest at certain times, always Friday to Sunday. For the city sieges, both attacking and defending guilds may recruit up to 100 Bounty Bay Online Coin for additional support. So there may be up to 500 players engaged in battle during a siege. Before the cities can be stormed, assailants must first battle naval forces and artillery in the heavily defended coastal waters. City defenders also present a challenge on land, trying to prevent the attacking forces from destroying their fortress' flag within a certain time period. If the defenders aren't able to hold their ground, the siege is considered a success and the winning guild receives useful items. For example, resource cities like Seoul, Barcelona, and Athens reward conquerors with valuable resources.