Located in Brompton cemetery in London lies the supposed tomb of Hannah Courtoy, given the nickname "the Brompton time machine". The cemetery itself is another of the "magnificent 7" created in the 19th century along with Highgate cemetery (there's a recent post about Highgate if you're interested). The cemetery has been frequent used in film and TV, including Sherlock with Benedict Cumberbatch. It features some stunning architecture, classical colonnades and underground catacombs full of ornate Victorian coffins in various states of disrepair.
The most famous grave, mentioned above is the Courtoy Mausoleum. The legends surrounding the tomb perfectly marry together two famous Victorian obsessions - weird science and Egyptology.
Erected in 1854, Courtoy's memorial is supposedly a collaboration between Joseph Bonomi (Egyptologist, sculptor) and Samuel Alfred Warner (naval weapon inventor, likely charlatan). The stories told about the tomb suggest a few things, the most well known that it is a time machine. Stephen Coates, a local musician and psychic researcher on a mission to unravel the tombs mysteries has suggested his research indicates the tomb may be a teleportation device, so more of a space travelling machine, rather than time travel, operating on a "London teleportation network" that has points within similar looking tombs in other graveyards around London. Another theory is that its a teleportation device to an identical tomb based in, some say Père Lachaise Cemetery, others Montmartre Cemetery in Paris. But, to understand how these stories came about, we need to begin with it's supposed resident, Hannah Courtoy.
Hannah, who was born Hannah Peters in 1784 as a young woman, around 20 years of age, went to work in the household of the elderly, yet wealthy merchant John Courtoy. During the time she spent there, despite never marrying, she had 3 daughters, Mary Ann (1801), Elizabeth (1804-1876), and Susannah (1807-1895). Despite the fact John Courtoy was 70 at the time, Hannah insisted he was the father - although many doubted this claim, basically believing her to be a gold digger, however paternity testing wasn't around then. Hannah took the name Courtoy and when he died a battle began over a disputed will, which wasn't settled until 1827. Hannah received a large amount of Cortoy's vast wealth (sources claim this was around £250,000 at the time, so around £19,000,000 today) , the rest going to his family from a previous marriage, but the will was heavily contested as by all accounts John held a strong affinity for his former family, and the dispute centred on the legitimacy of his Last Will and Testament made in 1814. In 1810, despite having given his name to Hannah's three daughters who were all baptised as 'Courtoy', John Courtoy made a Will leaving the bulk of his estate to his former partner Mary Ann Woolley and her children. In 1814 a second Will was made, effectively reversing his previous bequests, with Hannah and her children now emerging as the principal beneficiaries. This caused many to question why, in the space of only four years, John Courtoy had changed his mind so dramatically especially with the doubts about the claims they were indeed his children.
Anyway, now ridiculously wealthy, Hannah lived a lavish lifestyle and was able to follow her passions of Egyptology, beginning a "friendship" with Joseph Bonomi, a notable Egyptologist, artist, sculptor and museum curator, who is buried a stones throw away from the tomb. He was among the first to decipher some of the hieroglyphic texts found in the Valley of the Kings. The story goes that Bonomi discovered the secret of time traveling from hieroglyphs he saw on one of his expeditions. He then fascinated Hannah with stories of Egyptian iconography and astrology and was also said to have dealings in the occult. He also introduced her to inventor, Samuel Alfred Warner. Some claim Warner was a genius who invented the torpedo, and notably an 'invisible shell', or as Stephen Coates describes it, "a bomb that could be teleported a short distance – a kind of psychic torpedo”. However, others belive he was a fraud who tried to convince The British army to finance his development of several advanced weapons, too advanced to actually exist. Incredibly however, the Royal Navy did allow Warner to conduct several demonstrations, in which at least one ship was destroyed, however this failed to give conclusive proof of the weapons efficacy.
Supposedly, the two men convinced Hannah to finance their secret project - to design and build a mausoleum that would actually be a time machine. By placing their device in a cemetery, they ensured that no one would interfere with their journey through time, since cemeteries are rarely changed.
Hannah died in 1849, but the Mausoleum itself was finished in 1854, 5 years after Hannah passed away, with Warner dying shortly after the tombs completion under suspicious circumstances. 3 main rumours surround his death, with some saying he was killed by Bonomi to prevent him sharing the secrets of the project, others claim it was because of something he discovered while creating ammunition for the Navy. Another rumour is of course that Warner never died at all and simply travelled in space and/or time and vanished... Basically that Warner was/is in fact Dr Who. 
Both Bonomi and Warner are buried in Brompton, with Bonomi in a modest grave in the direct vacinity of the tomb (pictured), which shows a depiction of Hannah's tomb and Anubis, the Egyptian god of death, looking in the direction of the tomb. Warner is buried in an unmarked grave nearby.
Another detail that supports the story of the mausoleum being a time machine is that there are also strange wheel motifs on the bottom of the mausoleum door. However, I hate to be a spoil sport here but after spending a long time looking up Victorian burial practices, I can fairly confidently suggest (I'm no expert, just a nerd) these are in fact just vents commonly seen in Mausoleum doors at the time, to prevent a build up of gasses and smells from decomposition, as it was common for the Victorians to pack up afternoon tea, go down to the family crypt, crack it open and have a picnic, but that being said, the choice of design is certainly interesting, and may be connected to the hieroglyph style motifs around the bronze door, which also seems to bear the initials H and C, not too sure on the other two. On all four sides of the tomb is a large circular hole in the top, containing what appears to be a glass orb, with 8 smaller holes surrounding it. Some say that it looks like a clock or dial was supposed to be in that place, others suggest they are crystals that power the time machine, with some claiming they're powered by the sun, perhaps giving some backing to claims of Bonomi's use of the Occult. Perhaps he did indeed find the secret to time travel during his time working as an Egyptologist, or perhaps, given its a mausoleum and Bonomi's headstone bears an image of Anubis, he found some way to create a portal to the afterlife, or maybe even resurrection. Furthermore, for almost every structure in the Brompton Cemetery there exists an architect’s plan, but not for this mausoleum. To make everything even more mysterious, the key of the mausoleum went missing, with some saying it went missing in the 70s, others say its been missing for 150 years. Either way, no one in living memory has been inside by all accounts.
Another interesting fact about the tomb is that it rests upon a crossroads. Crossroads have long history of being seen as places of power and magic across multiple religions and belief systems including Slavic paganism, Greek and Roman mythology, Hoodoo and Voodou. They are sometimes seen as points of great energy, and portals to other realms, even times. They are sometimes said to be where the veil is most thin between this world and the next, and ones within graveyards are said to be particularly powerful. It is also unusual as burial on or under a crossroads was usually reserved for those viewed as truly evil, so if the deceased's soul does decide to rise again, it'll get confused and won't know which road to take. I lived on a crossroads in Liverpool, on Tithebarn Street which is an example of this, below the now busy crossroads it's said a vampire is buried there, for the above reason. However, if he did decide to dig his way through the concrI'm sure he'd be more confused by the 17 foot neon yellow Superlambanana than a crossroad. Although we did regularly have unexplained cupboard wind, where the doors would blow open for no reason and sometimes you'd get a gust to the face getting a cup out, maybe it was connected, maybe it was cheap student accommodation, who knows.
As this has been pissing me off for about 4 years at this point, I have spent more time than I'd like to admit digging through the Internet to find anything I can on the thing. I did find the following on RBKC local studies regarding the tombs creator, after local historian David Walker had first seen it in the 1980s:
"Wondering who was inside this Egyptian style mausoleum I consulted the Survey of London and discovered that it was built for Francis Jack Needham, 2nd Earl of Kilmorey.
From other sources I learned that the Earl was apparently dissatisfied with this potential resting place and had another Egyptian mausoleum built for him near his house in Twickenham"
I also found a comment on an old message board, which of course I can't for the life of me find again, from a chap who said he'd lived next to Brompton for years, and would volunteer helping with maintenance and although he didn't have a name, gave a similar account that the tomb was made for a wealthy patriarch who didn't like the final design and it was therefore abandoned.
Either way, the stories behind this tomb are fascinating, and I desperately hope they finally get the key so we can see what's behind that bronze door.