61 card sets with photos of nature: landscapes, animals, thematic close-ups.
Covers all major Earth biomes:

• caves
  
• desert
  
• forest
  
• grass
  
• ice (Arctic, Antarctica)
  
• jungle
  
• mountains
  
• ocean bottom
  
• rivers
  
• Savannah
  
• sea
  
• swamp
  
• tundra