Climbing the six Abels in the brutal Western Arthurs Range, located inside the World Heritage-listed Tasmanian Wilderness Area that covers 20% of the island, necessitates a walk through such difficult mountain terrain that it can take walkers up to two weeks to hike what is often described as the most difficult bushwalk in Australia.

BBC: Tasmania's greatest mountain quest

Benedetti will lead the ensemble as they prepare and perform what is billed as "one of the most difficult and exciting pieces for string orchestra - Bartok's Divertimento - a piece selected to challenge the players and encourage musical excellence".

BBC: Scotland

Let me begin, first of all, by thanking Ruth for allowing Jack to serve in what I know is one of the most difficult jobs in Washington.

WHITEHOUSE: President Obama on the Resignation of Chief of Staff Bill Daley | The White House

What makes the Hines story unusual is that it concentrates on the most complex, difficult projects, the ones that require an inordinate amount of money and planning up front in exchange for a greater return later on.

FORBES: Second Empire

What makes the Hines story unusual is that the firm concentrates on the most complex, difficult projects, the ones that require an inordinate amount of money and planning up front in exchange for a greater return later on.

FORBES: Second Empire

After all, the company is coming off a quarter where it exceeded revenue estimates in what was one of the most difficult quarter for the entire sector.

FORBES: Why Apple Touching Bottom Is The Wrong Question To Ask

Global peace is the most noble goal of humanity -- but what does it entail and why is it so difficult to achieve?

CNN: Quest for peace