Specifying a VPC in a CloudFormation template for an EC2 instance

I'm launching an EC2 instance via a CloudFormation template, however, the specified instance t2.micro requires a VPC.

How do I specify a VPC in the CloudFormation template?

Here's my template:

{
    "Description" : "Single Instance",

    "Resources" : {
        "EC2Instance" : {
            "Type" : "AWS::EC2::Instance",
            "Properties" : {
                "ImageId" : "ami-b73b63a0",
                "InstanceType" : "t2.micro",
                "KeyName" : "my-key",
                "Tags" : [
                    {
                        "Key" : "Name",
                        "Value" : "test"
                    }
                  ]
            }
        }
    }
}