Cheomseongdae Observatory, Asia's oldest existing astronomical observatory and a UNESCO World Heritage site, is easily accessible on foot, by bicycle, or local bus within Gyeongju's flat historical park area. Entry to view the structure from outside is generally free, though nearby attractions may have small fees. A solo visit is perfectly adequate to appreciate this ancient Silla structure, taking about 15-30 minutes for the observatory itself, though visitors often spend several hours exploring the vast surrounding historical complex. It is open year-round, with spring's cherry blossoms and autumn's foliage offering particularly scenic backdrops, and is especially beautiful when illuminated at night.