Mexico City Travel Suggestions?

Good day:

We are doing a last minute 4 day trip to Mexico city

Any insights tips, suggestions - Thank you. 2 seniors and a 35 yo

ATM Question: When we travel we typically use a checking account for local cash withdrawls at a Bank ATM. Any specific concern in Mexico. Just FYI, as a precaution, the checking is a travel checking and not our usual one.

Thank you

JTraveler