Contrary to the general idea, deserts are not always located in warm areas and do not represent only sand dunes.
Here are the largest deserts in the world:

1/ Antarctica (polar desert)
Area: 14 million km2
Location: Antarctica

2/ The Arctic (polar desert)
Area: 13.7 million km2
Location: United States, Canada, Greenland, Iceland, Norway, Sweden, Finland, Russia

3/ The Sahara (hot desert)
Area: 9 million km2
Location: Algeria, Egypt, Libya, Chad, Mauritania, Morocco, Tunisia, Sudan, Niger, Mali

4/ The Arabian Desert (hot desert)
Area: Over 2.3 million km2
Location: Jordan, Iraq, Kuwait, Qatar, Oman, Saudi Arabia, United Arab Emirates, Yemen

5/ The Gobi Desert (cold desert)
Area: 1.3 million km2
Location: China, Mongolia

6/ The Kalahari Desert (hot desert)
Area: 900,000 km2
Location: Angola, Botswana, Namibia, South Africa

7/ Patagonia (cold desert)
Area: 787,291 km2
Location: Argentina

8/ The Great Victoria Desert (hot desert)
Area: 647,000 km2
Location: Australia

9/ The Syrian Desert (hot desert)
Area: 520 km2
Location: Syria, Jordan, Iraq

10/ The Great Basin (hot desert)
Area: 492 km2
Location: United States

11/ The Chihuahua Desert (cold desert)
Area: 450,000 km2
Location: Mexico, United States

12/ The Great Sand Desert (hot desert)
Area: 400,000 km2
Location: Australia

13/ The Karakum Desert (hot desert)
Area: 350 km2
Location: Turkmenistan

14/ The Colorado Plateau (cold desert)
Area: 337 km2
Location: United States