Altar

A place set apart for spiritual rituals or prayers/worship, whether good or bad.

It is symbolic of sacrifice or offering with a specific intent, Jesus, Lamb of God, worship, repentance, prayer, gratitude, self-denial, change of heart

There are evil altars and good altars

Altars are an access into the supernatural

Then Noah built an altar to the Lord, and took of every clean animal and of every clean bird, and offered burnt offerings on the altar. (Genesis 8:20)