The first movie ever made is widely considered to be "Roundhay Garden Scene," created by French inventor Louis Le Prince in 1888. This short film, lasting just about 2.11 seconds, features four people walking in a garden in Roundhay, Leeds, England. It is notable for being one of the earliest examples of motion pictures, predating larger works like Thomas Edison's "The Kiss" (1896) and the Lumière brothers' films. While "Roundhay Garden Scene" is often credited as the first, the history of film includes various early experiments and innovations.

The movie "Milestones," directed by Joan Micklin Silver and released in 1975, is notable for its portrayal of the lives of two couples navigating the complexities of love, relationships, and societal expectations in a rapidly changing America. However, if you're referring to a film that created a significant milestone in the history of world cinema more broadly, "The Birth of a Nation" (1915) is often cited for its groundbreaking techniques, despite its controversial content. It marked a pivotal moment in film narrative and technical innovation.

In the context of the film "Milestones," movies were traditionally made using celluloid film stock, which is a flexible strip of plastic coated with a light-sensitive emulsion. This material captures images frame by frame when exposed to light in a camera. The most common formats were 35mm and 16mm. However, the industry has largely transitioned to digital filmmaking, which utilizes electronic sensors to capture images, allowing for easier editing and distribution while reducing the physical space required for film storage.

Movies have evolved significantly over time, reflecting changes in technology, storytelling, and audience expectations. Early films were silent and focused on visual storytelling, while the introduction of sound in the late 1920s transformed the industry. The rise of color films in the 1930s added a new dimension, and advances in special effects have allowed for more imaginative narratives. Today, digital filmmaking and streaming platforms have democratized access to filmmaking and distribution, leading to a diverse range of voices and styles that cater to global audiences.