Real Madrid and Arsenal barely broke a sweat, putting themselves in strong positions to qualify for the knockout stages. Manchester City, however, are in danger of suffering elimination after collapsing and letting a two-goal lead go to lose 4-2 to Paris Saint-Germain at the Parc des Princes inspired by the brilliance of Ousmane Dembele.

Manchester City's head coach Pep Guardiola reacts during a Champions League opening phase soccer match between Paris Saint-Germain and Manchester City at the Parc des Princes in Paris, Wednesday, Jan.

Paris Saint-Germain produced a stunning second-half fightback as they recovered from two goals down to beat Manchester City 4-2 in a Champions League thriller on Wednesday, a result which leaves Pep Guardiola's side still at risk of an early exit.

Jack Grealish recognises Manchester City are now playing knockout football in the Champions League before the latter stages have even begun. City are in danger of failing to progress beyond the first phase of the competition for the first time since 2012-13 after a calamitous 4-2 defeat at Paris St Germain on Wednesday.

A man from Derinkuyu, in the Nevsehir province of Turkey was renovating his basement. Using only a sledgehammer, he broke through one of his walls; and felt cool air coming in from the other side. Inside he found a small room-sized cave.