What features should I look for in an expedition touring bicycle to ensure it is suitable for long-distance travel and rugged terrain?

When choosing an expedition touring bicycle for long-distance travel and rugged terrain, look for features such as a sturdy frame made of steel or titanium, wide and durable tires for stability and traction, a comfortable saddle for long hours of riding, multiple gear options for varying terrain, strong brakes for safety, and mounting points for racks and panniers to carry gear.