Two bad ideas!
Firstly, I must say, these were bad ideas in my opinion - you might have a different view! However, with the benefit of hindsight, both proposals, taken seriously at the time, would probably now be regarded as architectural eyesores, given the beauty of both their locations.
John Charles McQuaid, Archbishop of Dublin from 1940 to 1973, and a supporter of the cathedral project.
In 1930, the Roman Catholic church purchased the gardens of Merrion Square, a twelve and a half acre former private park for residents, for the sum of £100,000. It was bought with the intention of building a proper cathedral for their congregation, with Dublin's Pro-cathedral, as the name implies, being a temporary solution to their needs. It is a complete quirk of history that Dublin has two wonderful medieval cathedrals, within five minutes walk of one another, and both belong to the Church of Ireland. This reflects the fact that under British rule, the Church of Ireland was the official established religion of Ireland until 1869, despite the fact that the majority of Irish were Roman Catholic. Indeed, the Penal laws first enacted in the 1690's had made it difficult for Irish people to practise their religion and these discriminatory laws were not repealed until 1829. In 1815, shortly before Catholic Emancipation, consideration was given to building a Catholic cathedral on a site on Sackville Street, as O'Connell Street was then known, but the authorities lost their nerve and insisted it be built on a secondary street. Architect Francis Johnson went on to design and build the General Post Office on the Sackville Street site.
From the foundation of the state, the Catholic Church grew increasingly powerful and embarked on a wave of church building throughout the country, particularly in the newly built Dublin suburbs. These churches were built to cater for large congregations, and in 1938, the Church of Saint Peter and Saint Paul, often mistaken for a cathedral due to it's size, was built on a prominent site in Athlone - pictured below.
Drawings of the proposed Merrion Square cathedral were created but as the church was concentrating their efforts on the new churches the project never moved beyond an aspiration. However, looking at the bulk of the proposed building, and given the sensitivity of the location, across the street from Leinster House, and in the heart of a Georgian square, we can be grateful that the project did not proceed. Ireland did not have planning permission laws until as late as 1963, and public consultation on church projects was unlikely to have existed. Dublin might well have ended up with a huge 1930's cathedral, perhaps like this one drawn by L F Dowling, kept in the Dublin Diocesan archives.
It is worth mentioning that during the period of ownership of Merrion Square by the church, the gates were kept firmly closed. Access to the square could be purchased by the residents for £10 per year. Archbishop McQuaid died in 1973 and in 1974 his successor, Archbishop Dermot Ryan formally abandoned the idea of the cathedral and handed the gardens over to Dublin Corporation. They have turned it into the wonderful sculpture filled, landscaped park that is enjoyed by both locals and visitors to the city.
It is also worth mentioning that this was not the first time that Merrion Square had "dodged a bullet" in terms of over ambitious building projects. The huge obelisk known as the Wellington Memorial was originally to have been located in Merrion Square in the 1820's. However, in an early demonstration of "nimbyism", the wealthy and influential residents objected, and the obelisk was erected on a far larger site in the Phoenix Park - a far more appropriate site, to be fair!
The second "bad idea" is closer to home. In fact, if it had gone ahead, I would be able to see it from my kitchen window!
Charles Stewart Parnell, Wicklow resident, and leader of the Home Rule League, died in 1891. In Bray, a number of his admirers formed a committee to fundraise for a memorial and a number of designs were considered. One apparently involved an Irish Wolfhound, looking east from the Sugarloaf. Another proposal was for a thirty foot lighthouse with prismatic lenses to reflect the sunlight, and to be lit at night. The suggested location for this was the summit of Sugarloaf! This may have been the brainchild of Bray resident, Professor Edmond Fourneir D'Albe, a polymath with many fingers in many pies. He was involved in the Gaelic League, was a distinguished astrophysicist, and mathematician, stood for election to Bray Council, and was President of the Esperanto Society - in fact he translated some of the Book of Lismore from Irish to Esperanto!
The design for the lighthouse was selected in 1896 and and by 1898 funds raised amounted to £84. However, the unveiling of the Parnell Monument in Dublin in 1911 meant that the Wicklow project was gradually forgotten and the funds raised languished in an account for many years. In the 1950's a committee decided to use these funds in a very sensible way and they part funded the children's section of Bray library. They also commissioned the distinguished Breton sculptor and Bray resident Yann Goulet to create a bust of Charles Stewart Parnell which is on display in Bray Library.
And what might we have ended up with on top of Sugarloaf, surely one of Ireland's most climbed mountains ( though technically just a hill at 505 m!)? The photo below shows a very similar lighthouse which shines red, green and white lights, built on the southern shores of Lake Como to commemorate Alessandro Volta, an electrical genius. Imagine this shining down on Kilmacanogue, Calary, and Bray! I for one am glad that the summit of Sugarloaf has remained unlit and unbuilt upon!