France's iconic Eiffel Tower was closed Sunday after three people carrying "rucksacks" were seen scaling the outside of the structure, according to the Daily Mail.

A helicopter was seen circling the monument about 9:00 a.m., as an added measure of security.

With a definite heightened security since the recent threats from ISIS and al-Quaeda on the landmark, as well as the August take down of an armed gunman who had plans of carrying out a mass shooting on a Paris-bound train, France is taking every threat very seriously, according to the Independent.  It is already in the highest state of alert.

In 2014, French officials uncovered a plot to attack the Eiffel tower when they arrested an Algerian butcher living in the south of France. Ali M., the suspect, had encrypted notes about al-Qaeda targeting the Eiffel Tower, planes "at the point of take-off" and nuclear power plants, according to the International Business Times.

There is speculation that it could be extreme parachutists, since they have disappeared completely, but the French security forces are taking all necessary precautions.

7 million people a year visit the Eiffel Tower, paying to go up the tower originally built for the 1889 World's Fair.

The Eiffel Tower reopened around 2 p.m., five hours late, while security checked the structure thoroughly.