It is difficult to summarise the evidence in support of the landings because there is so much of it. However the following points cover the main bodies of evidence:
The most compelling evidence is the 382 kilograms of moon rocks brought back to Earth by the Apollo missions. These samples have been independently analysed by geologists from all over the world for more than thirty years. The conclusion is basically 100% unanimous - these rocks could not have originated on Earth and must have come from the moon.
Perhaps these rocks were brought back by robotic missions? Not possible - the technology was not available at the time.
What about moon rocks found in Antarctica? Finding 382 kilograms of diverse rocks - exactly the kind geologists would have chosen to study - seems somewhat unlikely.
There is a massive repository of film and photographic evidence. Although many of the hoax theories attempt to discredit this evidence, none succeed. In any case the sheer volume of photographic evidence is staggering.
At the peak of the Apollo programme, nearly half a million people were directly involved. Although most were far from mission control, it seems highly unlikely that a hoax could have been kept secret from them all. Notably, not one single employee has come forward with any credible hoax evidence.
The Apollo 11 mission left a laser reflector at its landing site. This reflector has been used ever since to measure things such as the precise distance to the moon. Anyone with the correct equipment can use it.
The Russians were watching the USA space programme like hawks and analysing everything the Americans did. If there was the slightest suggestion that a hoax was happening, the Russians would have been falling over themselves to tell the world about it.
In January 2004 President Bush announced a new initiative to return to the moon, and called on other nations to become involved in the project. Why would he do this (especially the part about inviting other countries to participate) if the landings had been faked?
Finally, did NASA actually have a motive to attempt a hoax? If not, the rest of the argument is irrelevant.
Next Page: A Question of Motive