This is one of the most popular databases, thanks to MongoDB and CouchDB. This type of database stores the information in a JSON-based document. As this is a key-value store, you can save complex objects that contain arrays, nested documents, and other different data types. For example, you can save the following person in the JSON document:

{
  "identification" : "PE0022458197",
  "name": {
    "firstName": "Jack",
    "LastName": "Ma"
  },
  "age": 45,
  "addresses": [ 
    {"country": "Peru", "address": "MyTown PE#32"},
    {"country": "China", "address": "OtherTown CH#44"}
  ]
  ...
}

As you can see, you don't need to store the addresses in a different document (or a table in SQL databases); you can perfectly store them in the same document (or a table in SQL databases).