Suwon (수원) is located 30km South of Seoul, and it's easily reached from the Capital by subway's Line 1 in about one and a half hour. It's the capital and the largest city in the Gyeonggi province (경기도) that surrounds Seoul, which is indipendent administratively.
The city is famous above all for the Hwaseong Fortress (화성, it means brilliant fortress in korean), it was built from 1794 to 1796 by King Jeongjo from the Joseon Dinasty. The architecture combines both oriental and westerner elements, and it's quite different from all the other architecture expressions in Korea. In 1997 UNESCO designated the fortress as a World Heritage.
I really recommend to visit the city and the Fortress, it's absolutely wonderful and impressive.

JavaScript must be enabled in order for you to use Google Maps.
However, it seems JavaScript is either disabled or not supported by your browser.
To view Google Maps, enable JavaScript by changing your browser options, and then try again.