Ukrainian President Petro Poroshenko cancelled a visit to Turkey over the 'rapidly deteriorating situation'
Obama’s proposal for air strikes on Islamist fighters in Syria carries significant risk, experts warn
Newsweek reports on how the humiliation of an American has led to a surge of recruits among university graduates
Israelis are wary of Syrian rebels taking a Golan Heights border post, Marc Schulman reports
Monarch butterflies are in trouble due in part to a decline of milkweed plants, on which their young feed.
New research suggests that pollution in cities produces environments that mimic earth's future climate.
Einstein’s theory of relativity only makes sense if our world is a hologram, scientists say.