Explore the hidden depths of HTML in this eye-opening conference talk from CSS Day 2016. Delve into lesser-known HTML elements, attributes, and technologies that can enhance your web development projects. Learn how to leverage powerful features like modal dialogs, iframes, sliders, and autocomplete without relying on JavaScript. Discover the potential of structured data, microdata, and Schema.org vocabularies to improve your website's search engine results. Gain insights into HTML5 elements, download and file attributes, validation techniques, and RDF. Challenge your assumptions about HTML's capabilities and uncover new ways to create more efficient, semantic, and feature-rich web experiences.