The OpenStreepMap project provides their database for download. This is called the OSM planet dataset, which has a size of several gigabytes and contains the spatial data (e.g., roads, forests, buildings) of the whole world. The dataset is encoded in different data formats (e.g., XML or OpenStreetMap Protocolbuffer Binary Format). To be able to import the dataset into systems that are capable of handling spatial data, the data needs to be converted into GeoJSON.