James Bond 007 for Gameboy Easter Egg - The Jeweled Egg

When you're at Kurdistan, (the second level), and you're in front of the cave entrance, don't go in the cave! Instead, go right until you hit the rock wall. You should hit a secret passage and you'll walk right through the wall! Keep walking along the secret passage in the wall. Eventually you'll reach the end of the passage and you'll be in a small opening where a man is sitting down. If you talk to the man he'll give you a secret jeweled egg if you don't anyone where he is hiding. In the next level, Marrakech, you can trade this jeweled egg for an underground pass, which you let's you access the underground passage ways all around Marrakech. You cannot get into the passages unless you have this egg.