Final answer:
The central message of this poster is emphasizing the importance of global unity and equality.
Step-by-step explanation:
The central message of this poster is emphasizing the importance of global unity and equality. The words at the top of the image, 'Freiheit, Gleichhight, and Brüderlichkeit' (Liberty, Equality, and Fraternity), along with the Karl Marx quote, and the names of countries and continents, all work together to convey this message. The image and words create a sense of solidarity and inclusivity, promoting the idea that all people should have equal rights and opportunities.