Windows 10 IoT Core is a specialized version of Windows 10 compiled for ARM devices like the Raspberry Pi 2. It allows developers to write .NET and C++ applications for IoT devices and access device capabilities like GPIO pins. IoT Core applications can integrate with Azure services like Event Hubs to process and analyze sensor data from devices in the cloud. The document provides an overview of IoT Core and demos a simple distance-sensing application with a Raspberry Pi that streams data to an Event Hub.