We have a long layover at Mexico City on a Sunday morning for 7 hours, with no baggage with us. We will already have a Mexican visa, so we are wondering if we can get a cab at the airport to take us around and back to the airport. Is it safe, and feasible in such a short time? If so, what are 2-3 highlights we can ask the cab driver to show us? Really appreciate if someone can advise on this.