One of the main reasons that the Three Gorges dam was built was to prevent flooding further downstream. The need for a dam was highlighted in 1954 when people were killed as a result of flooding of the Yangtze River.
Arab Spring refers to the democratic uprisings that arose independently and spread across the Arab world in 2011. The movement originated in Tunisia in December 2010 and quickly took hold in Egypt, Libya, Syria, Yemen, Bahrain, Saudi Arabia, and Jordan.
Revolutions of 1848. The Revolutions of 1848, known in some countries as the Spring of Nations, People's Spring, Springtime of the Peoples, or the Year of Revolution, were a series of political upheavals throughout Europe in 1848. It remains the most widespread revolutionary wave in European history.