* Savannah (with an "h") refers to the city in Georgia, USA. It's a proper noun, just like "London" or "Paris".
* Savanna (without an "h") refers to a type of grassland ecosystem characterized by scattered trees. This is a general term, like "forest" or "desert".
Therefore, the spelling "Savannah" is used specifically for the city, while "Savanna" is used for the biome in general.
Here are some examples:
* "I visited Savannah, Georgia, last summer." (referring to the city)
* "The African savanna is home to many fascinating animals." (referring to the ecosystem)
Let me know if you have any other questions about the English language!