An old conspiracy theory holds that the Titanic was actually switched with the sister ship Olympic before it sailed on its fateful voyage in 1912. The proofs are mostly coincidences and rumors, but the proof that convinces many people is the following set of photos.
Photo 1 – Titanic under construction with evenly spaced portholes.
https://www.theguardian.com/uk/2011/may/31/titanic-centenary-belfast
Photo 2 – Titanic when it set sail, with different portholes, suggesting it is the Olympic in disguise.
However, it took only a few minutes to find the following photo of the Olympic (supposedly the Titanic in disguise) from 1932, which also shows the same irregular portholes.
https://www.shipsnostalgia.com/media/rms-olympic.455381/
So theory disproved, the two ships had identical portholes and the two photos prove nothing except that the additional portholes where added to the Titanic later in the construction. Of course diehard believers can argue that the Olympic (Titanic in disguise) was modified after the accident to match the sunken Titanic (Olympic in disguise); conspiracy theories are malleable enough to withstand any challenge.