What could you expect to see in a mayan city?

Which of the following would be the most immediate effect of sanctions on a country?

What specific events led richard nixon to resign the presidency

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.