Complex sentence: Stephen Salyer is president and chief executive officer of the Salzburg Global Seminar, a non-profit organization based in Salzburg, Austria and Washington, D.C., whose mission is to challenge current and future leaders to develop creative ideas for solving global problems.
Split into simpler sentences: Stephen Salyer is president and chief executive officer of the Salzburg Global Seminar. Based in Washington, D.C. and Salzburg, Austria, the Seminar's mission is to challenge current and future leaders to develop creative ideas for solving global problems.