This book presents Peter d'Agostino's World-Wide-Walks project, providing a unique perspective on walking practices across time and place considered through the framework of evolving technologies and changes in climate. Performed on six continents during the past five decades, d'Agostino's work lays a groundwork for considering walks as portals for crossing natural, cultural, and virtual frontiers. Broad in scope, it addresses topics ranging from historical concerns including traditional Australian Aboriginal rites of passage and the exploits of explorers such as John Ledyard, to artists' walks and related themes covered in the mass media in recent years. D'Agostino's work shows that the act of walking places the individual within a world of empirical awareness, statistical knowledge, expectation, and surprise through phenomena like anticipating unknown encounters around the bend. In mediating the frontiers of human knowledge, walking and other forms of exploration remain a critical means of engaging global challenges, especially notable now as environmental boundaries are undergoing radical and potential cataclysmic change.