A landmark case is a court case that is studied because it has historical and legal significance. The most significant cases are those that have had a lasting effect on the application of a certain law, often concerning your individual rights and liberties.
The primary problem was inflation
During the Dust Bowl, people experienced dust storms which
had a detrimental effect on the environment and their livelihoods. People could
see mixture of soil erosion and winds caused the dust to fly freely and at high
velocities. As a consequence, animals such as birds perished from the resulting
suffocation and could be seen falling freely
I'd say the concept of equality, the publication of Common Sense, and successful revolutions
In much the same way as Christianity, Islam too gave a belief of a promised better life once life was over. If you cannot pay a man, convince him pay will come once dead.