are there any sites that are on the same Longitude/Latitude line as another one?

I did draw up a list which helped Els to generate the Equator and Arctic connections but here are the details that I came up with.

It is slightly different to what you ask but I hope it is of some use.

WHS that sit on major lines of Longitude/ Latitude
Prime Meridian: Greenwich*, Mont Perdu*, Tomb of Askia in Gao
Anti- Meridian: Wrangle Island*
Arctic Circle: Struve Geodetic Arc (I am sure there is a monument on the arctic circle but I could be wrong on this)
Tropic of Cancer: Buddhist Monuments of Sanchi
Equator: Lope - Cultural Landscape of Lope- Okanda, Mount Kenya, Galapagos Islands*, Quito*
Those with * are directly on the line the others are within 10km

With over 850 sites in even more locations (many of which cover quite large amounts of ground N/S and E/W) there are likely to be, purely by chance, a number of sites on a shared Latitude and Longitude - less of course if one defines the position to minutes and seconds rather than just degrees.
Early on in defining "Connections" we looked specifically for "significant meridians" - the Tropics, Arctic/Antarctic, Greenwich and of course the Equator - where we did find a "Connection". We had to limit the Arctic Connection to "Inside" rather than "On" the Circle and didn't find any others on the chosen meridians. We decided to limit the connection to those actually "On" the significant meridian (to the second!) rather than just "near" as the latter would seem to lose the "significance". As suggested above there may be a trio of sites sharing some nondescript meridian but would that be of any significance? The Northern latitudes would seem likely to provide the greatest chance following as they do the "hot spot" continents of Europe and Asia with relatively little sea