REMOVE

1. city gates
2. city walls

WHAT

1. architecture (object genr … (1)

WHERE

1. China (nation) (1)
2. Xi'an, China (1)

WHO

1. unknown Ming (1)

WHEN

1. 14th century (1)
2. 15th century (1)
3. 16th century (1)
4. Ming (1)