An employee cleans the logo at the Congress Hall in Davos, Switzerland, on Jan. 19, 2015. The world's financial and political elite will head to the ski resort this week for 2015's gathering of the World Economic Forum. The annual event runs from Jan. 21-24.

A worker prepares the sign at the entrance hall of the Congress Hall, the venue of the World Economic Forum, in the Swiss mountain resort of Davos on Jan. 19, 2015. More than 1,500 business leaders and 40 heads of state or government will attend the Jan. 21-24 meeting of the World Economic Forum to network and discuss big themes -- everything from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying program and the safe-haven Swiss franc rocketing.

Armed Swiss police officers stand guard on the roof of a hotel the day before the opening of the annual meeting of the World Economic Forum in Davos, Switzerland, on Jan. 20, 2015.

A Swiss special police officer observes the surrounding area from atop the roof of the Davos Congress Hotel in the Swiss mountain resort of Davos on Jan. 20, 2015.

Technicians setting up signs outside the Congress Hall in Davos, Switzerland, on Jan. 19, 2015.

A participant arrives by private helicopter for the World Economic Forum in the Swiss mountain resort of Davos on Jan. 20, 2015.

Participants of the World Economic Forum travel on a golf buggy next to the Congress Hall in Davos on Jan. 20, 2015.

A view of the Congress Hall, where the annual meeting of the World Economic Forum will take place in Davos, Switzerland, on Jan. 20, 2015.

Flags hang on the roof of the Congress Hall were the World Economic Forum will take place in Davos, Switzerland, on Jan. 19, 2015.

Swiss police walk along a street near the World Economic Forum venue in the Swiss mountain resort of Davos on Jan. 20, 2015.

The InterContinental hotel is seen through barbed wire in the Swiss mountain resort of Davos on Jan. 20, 2015.

Workers set up logos of the World Economic Forum at the Congress Hall in the Swiss mountain resort of Davos on Jan. 20, 2015.