nokia lumia 800 (codenamed 'sea ray') is a smartphone from nokia, first unveiled on 26 october 2011 at the nokia world 2011 event. it originally runs on windows phone 7.5 "mango"—it was nokia's first device to run the windows phone operating system and marked the company's shift from symbian for their smartphones. it was nokia's flagship upon the original release in europe in november 2011, and was thus also a highly important product for nokia's mobile phone business.