When Paul saw an altar to an unknown god in Athens, he used it to proclaim the one true God to those who were listening. Jesus came to earth so that we might come to know God through Him, the perfect representation of God, being Himself.
Because we have come to know God through Jesus, we look in our culture for ways that we might be able to point others to the gospel so that they too might move from ignorance and disbelief to knowledge and faith in Christ.