The ceasefire in Syria has begun, and it seems to be holding. According to the Guardian:
A fragile, temporary and partial cessation of hostilities has come into force in Syria after 97 fighting groups, as well as the Syrian government and Russian air force, signed up to a ceasefire.
A monitoring group said early on Saturday that fighting appeared to have stopped across most of western Syria
To be clear, because ISIS and Al-Nusra control such a larger portion of Syria, the ceasefire only applies to small (but critical) conflict zones. The areas affected by the ceasefire are in blue: