Seoul is one of the most populous cities in the world, home to some 10 million people in the centre plus 25 million in the wider metropolitan area. And yet Seoul is not a city that overwhelms visitors.If you are looking for a diverse travel destination in Asia, the South Korean capital is the perfect spot.The city is well-organised and easy to navigate, nestled among mountains and steeped in history – a history found not only in museums but out on the streets, on city walls and in palace courtyards.If you can, spend five days there. Even that is not enough to understand Seoul, but it gives you a chance to know why you would want to come back.Day one: the palaces of the Joseon kingsYour first day in Seoul is all about the kings. Gyeongbokgung – built in 1395, destroyed during the Imjin war (1592–1598) and reconstructed over decades – opens up behind its entrance gate like a city in its own right.The palace has sprawling ceremonial courtyards, curved roofs in shades of blue and green, and guards in historical uniforms who carry out the changing of the guard several times a day. The ritual is choreographed down to the last detail. But it is more than just a spectacle; it serves as a reminder that this place was the centre of power on the Korean peninsula for five centuries.