To win a place, pupils can sit a purpose-designed World Class Test or US pre-university exams.

BBC: Bringing on the brightest

About 300 of the roughly 46, 000 students who took the class with an MIT professor filed into test-taking centers around the world in the hopes of earning a "proctored honor certificate" from the class signed by the professor.

WSJ: Web Classes Grapple With Stopping Cheats