Adding to GeniusJack's comment:
Burası/Orası/Şurası = This/that place
They act as nouns and can therefore be the subject or object of a sentence.
Burada/Şurada/Orada = here/there (in this/that place)
They cannot be the subject or object of a sentence.
When you're showing a place, you say:
This place is Taksim square.
"This place" being the subject, has to be in the noun form: Burası.
If the sentence was: "Here, people drink tea."
"Here" is not the subject. In fact, the subject is "people" and the object is tea". So you would say: Burada, insanlar çay içerler.