The Largest ....

1. Island - Greenland 
2. Jail       - Rikers jail
3. Xmas tree- Sri Lankan Xmas tree
4. Zoo- Sri Venkateswara Zoological Park
5. Satellite- Ganymede
6. Dairy - Dairy Farmer of America 
7. Garbage dump- Estrulural landfill
8. Vegetable- Giant Cabbage 
9. Telescope - Gran Telescopic Canarus 
10. Wearable Turban - Major Singh(India)
11. Marker pen- Muhammad Dileef(India)
12. Comic book- Kodansha Ltd (Japan)
13. Hiking- Markus Appelmanu (Germany)
14. Flower- Rafflesia 
15. Word in English - pneumonoultramicroscopicsilicovolcanokoniosis