There are many bus stops and a subway station called Tiantan East Station (天坛东门站）very close to the entrance.

Many locals, specially the elders use the long corridor for social actitivies such as playing Chinese chess, singing Peking Opera, selling hand-crafted items, etc. It is an excellent place to mingle with the locals during the weekend or holidays.

The Hall of Prayer for Good Harvests (祈年殿) is a magnificent triple-gabled circular building, 36 metres in diameter and 38 metres tall, built on three levels of marble stone base, where the Emperor prayed for good harvests.

The Imperial Vault of Heaven (皇穹宇) is a single-gabled circular building, built on a single level of marble stone base. It is located south of the Hall of Prayer for Good Harvests and resembles it, but is smaller.
Here in the picture, a street vendor is selling small model for the Imperial Vault of Heaven.

The Circular Mound Altar (圜丘坛) is the altar proper, located south of the Imperial Vault of Heaven. It is an empty circular platform on three levels of marble stones, each decorated by lavishly carved dragons.

If you leave the Temple of Heaven from the South Gate, you can catch many public buses and connect to other point of interests such as the Forbidden city, the People's Square, etc which are all rather close.