Final answer:
The first two summer blockbusters were 'Jaws' directed by Steven Spielberg in 1975 and 'Star Wars' directed by George Lucas in 1977. These films established the trend of major film releases during the summer season.
Step-by-step explanation:
The term summer blockbusters generally refers to films that are released in the summer and are high-budget, high-profile releases that are expected to perform very well at the box office. The first two summer blockbusters are widely considered to be 'Jaws' released in 1975 and 'Star Wars' released in 1977. 'Jaws' was directed by Steven Spielberg, and 'Star Wars' was directed by George Lucas. These films set the precedent for future summer releases with their massive success in terms of audience reception and revenue generated.