Yongdingmen

The gate itself is a sight to behold. A pleasant stroll through a park from Tianqiao subway station and from one of the entrances to the Temple of Heaven. If you're lucky, you might catch a community orchestra named after the gate performing nearby in the afternoon.

Very large park with beautiful trees and full of places to enjoy nature. Perfect for kids. Attractions such as palaces and temples are amazing, but close early (5pm).

It's ok but I wouldn't go out of your way if your on a tight schedule

Beijing Central Axis runs from north to south through the heart of historical Beijing. It is defined by former imperial palaces and gardens, imperial sacrificial buildings, ancient city management facilities, ceremonial and public buildings and Central Axis roads remains. The Axis bears testimony to the evolution of the city exhibiting evidence of the imperial dynastic system and urban planning traditions of China. The location, layout, urban pattern and design of the Axis showcase the ideal capital city paradigm prescribed in the Kaogongji, an ancient text known as the Book of Diverse Crafts. The Central Axis originated in the Yuan Dynasty (1271-1368) that established Dadu, its capital, in what corresponds to the northern section of the Axis. The property also features later historical structures built during the Ming Dynasty (1368-1644) and improved during the Qing Dynasty (1636-1912).

Walk...

This is not a tourist destination, but stands a reminder of its former glory. The gate stands on a traffic island that is not easily accessible. From the East and West entrances, go through the underpass and locate a set stairs to the square. The gate tower is not accessible for entering. It's basically a park that you can observe locals fly kites or walk. Not more than 10 minutes to walk around the gate. Also it is a long walk from any of the nearest metro stations. If you are interested in the former gate entrances of the city walls, then theses sites are better: Qianmen (Zhengyangmen), Deshengmen, Dongbianmen (located in the Site of Ming City Wall Park). These sites are easily accessible by metro as well.

Really cool area. Near lots of other things so you can start in one area and just walk

Nice enviroment