Chiang Mai old town in inside the old wall which surrounded with parts of the old ruin wall and the moat. It was built 1296AD by King Mengrai from Lawajungarat Dynasty in the purpose to protect the city from the enemy which preferred to invade Chiang Mai at that time. Now a day, visiting to Chiang Mai, you could still see parts of the old ruing wall around Chiang Mai.
From one corner to the other is 1.63 kms.on each side with 5 gates for 4 different directions. However the longest is on the north side with 1.67 kms. As there are many fights in the old day, the walls were destroyed and restored many time. The first time was in the reign of King Kawila as the fisrt king of Lanna Kingdom and from the record by King Thumma Langa in 1818AD.
However there are many times that the walls were restored, but still keep the old bricks and the shape as in the old days as much as the officers could do. Now a day, the old wall and the city moats is still graceful and you could walk around for taking pictures. However we are not allowed you or visitors to climb over the wall as you have to show the respect the the place as well as the ancestors who had fought to protect the old city over the wall. You could also see the sign shown at the base of the old city walk.
Jogging and walking for exercise is the thing you could do in term of seeing the old town. Also the mixture of the old and new architect as the town and the surrounding have already developed.
Walking in the old town and the old city wall is not a bad idea if you prefer to. Because you could also see the temples and pay a visit in the temples as most of them open for the public. Just dress politely and well behaved.