Getting to Greenland

Are there international cruise ships to Greenland? Can I fly directly to Greenland from Denmark? Can I fly directly to Greenland from Iceland? Can I fly directly to Greenland from North America? Can I travel to Greenland by ship or ferry? How do I get to Greenland? How far in advance should I book flights to Greenland? How long does it take to fly to Greenland? Which airlines fly to Greenland? Which airport should I fly to in Greenland? Which countries have direct flights to Greenland?