Change Is the Only Constant: The Wisdom of Calculus in a Madcap World. Orlin, Ben, Black Dog & Leventhal, 2019. A book in which each chapter explains a concept from mathematical analysis in an engaging way. Although the tone is informal, some background knowledge is recommended.
El libro de las matemáticas. A. Pickover, Cliffor, ILUS BOOKS, 2014. A book that presents mathematical concepts in chronological order, each accompanied by an illustration.
Practical Conic Sections: The Geometric Properties of Ellipses, Parabolas and Hyperbolas. Downs, J. W., Dale Seymour Pubn, 1993; reissued by Dover Publications Inc. in 2003. The first part presents a broad catalogue of theoretical and practical methods for constructing conic curves. The second part focuses on applications of conics, especially properties of surfaces of revolution.
Videos
Archimedes Tube. YouTube channel with detailed explanations of advanced mathematical concepts.
Derivando. YouTube channel for mathematical outreach. In each video, Eduardo Saenz de Cabezon presents mathematical ideas and results in a clear and simple way.
Mathologer. YouTube channel with detailed explanations of advanced mathematical concepts.
Numberphile. YouTube channel directed by Brady Haran, where mathematicians present concepts and ideas visually and clearly. It is one of the most popular mathematics channels.
3Blue1Brown. YouTube channel with excellent visual explanations of mathematics.
Websites
es.khanacademy.org. A learning website whose goal is to provide free, high-quality education for anyone, anywhere. Its catalogue ranges from basic education to university level.
MacTutor History of Mathematics Archive. Website by O’Connor, John and Robertson, Edmund with biographies of notable mathematicians and detailed articles on the history and development of mathematics.
es.mathigon.org. A complete website with courses, applications and activities for learning mathematics.