What is the best way to approach age verification?

Question

I want to verify that everyone that visit my website is least 18 years old. What would be the best approach in order to do it?

I think that the best approach is to send a cookie after the user clicks over the checkbox. Is there any better way to do this?

Example:

Answer 1

I would look into 3rd party authentication services like Auth0 (https://auth0.com/). I find if you allow people to use Social Networks that require their age, you are more likely to collect verified information.