President Obama: 'I will not get to see this again'
US President Barack Obama has taken the oath of office for the second time.
Mr Obama said: "I am not going to see this again" as he surveyed the hundreds of thousands on the National Mall.
Under the US constitution, presidents are only allowed to serve two terms.
Former Presidents Bill Clinton and Jimmy Carter, along with dozens of senators, congressional leaders and other dignitaries attended the event at the US Capitol.