Phonsavan is the capital of the Xieng Khouang Province. It is located 1100m above sea level. The major tourist attraction here is the Plain of Jars. So it is advisable to visit during the dry season as the route to those sites are not tarred and can be very muddy and slippery during the monsoon season.
Spend a day or two to visit the gigantic jars and make some time to the MAG UXO Visitor Information Centre and Xieng Khuang UXO Survivors Centre. Some tour packages include visit to the nearby Tad Ka Waterfall, Hmong Village and Mulberry Farm.