In the UK, the Metropolitan Police says its investigation into the disappearance of a teenager from West London is the biggest search deployment since the London bombings in 2005.
600 officers from eight forces have been involved in the search for Alice Gross.
25 square kilometres of open land and five-and-a-half kilometres of canals and rivers have also been examined.
14-year-old Alice Gross was last seen on the afternoon of Thursday, August 28th. Police in England have been appealing to the public for any information about her disappearance, including anyone who may have been speaking to her on social networks in the days leading up to her disappearance.
41-year-old Arnis Zalkalns has been named as a suspect in Alice's disappearance. He has not been seen since September 3rd. A Metropolitan Police statement said "friends and family of Arnis have told police that his disappearance is completely out of character, they are very concerned for him."
A reward of £20,000 (€25,400) is being offered for anyone who provides information that leads police to find Alice Gross.