Fetching details from the dictionary...
that; that thing
that person
then; that time
that place (over there)
down there (i.e. one's genitals)
period; menses
あれは一体何ですか。
What on earth is that?
あれから三年経ちました。
Three years have passed since then.
あれが東京タワーだと思うよ。
I think that's Tokyo Tower.