The other stands over 4,000 miles and an ocean away at the foot of St Edmund Pettus Bridge in Selma, Alabama; a plaque honouring the 600 protesters who were trampled, truncheoned and teargassed by Alabama state troopers while demonstrating for the right of black people to vote on March 7 1965.
Both events were named Bloody Sunday. Both resonated far beyond the small towns in which they took place to the very democratic fabric of the nations in which they occurred. But the second was erected by the Alabama Historical Commission, a federally funded body dedicated to "raising the awareness" and "reflecting the heritage of all Alabamians". The first exists solely thanks to the nationalist community of Derry. They not only had to mourn their dead but ensure that the injustice that killed them was not forgotten either.
Today may herald the beginning of the end of that incongruity. As Lord Saville of Newdigate begins to take oral evidence at Derry's Guildhall this morning in the inquiry into Bloody Sunday, the nationalist community is feeling cautiously optimistic. "My greatest hope is that the truth of what happened on the day is finally told," says Patricia Macbride, the manager of the Bloody Sunday centre in Derry. "That the people killed and injured on the day are finally vindicated as innocent and that those who were responsible are held accountable for their actions."
It is a substantial wish list, punctuated with scepticism. They have been here before. An inquiry in 1972 by Lord Chief Justice Widgery effectively exonerated the army of all wrongdoing, arguing only that some of their actions had "bordered on the reckless". More recently the army has admitted to destroying rifles that could have provided fresh and vital evidence to the inquiry, even after Lord Saville asked the Ministry of Defence to keep them safe.
Nonetheless, Saville already promises far more than Widgery could ever deliver. The Widgery report was a 39-page document, written in 10 weeks. The Saville tribunal has already been running for a year and a half, and has collected around 60,000 pages, more than 5,000 photographs and 36 hours of videotape.
As such, Saville has the potential to do for Northern Ireland what Macpherson did for Britain. It could confirm what a minority has been insisting for years, by elevating a long-held grievance to an established fact. It might illustrate how those responsible for maintaining law and order can and do use bureaucracy, malice and prejudice to ensure that those facts never emerge. And, by drawing a clear line of command from the pen pushers to the army snipers, it could show that the flaws that brought them about are not individual and erratic but institutional and endemic.
The parallels are not lost on locals here. "We have every sympathy with the way Neville and Doreen Lawrence were treated by the police," says Mickey McKinney, whose brother Willie was shot dead on Bloody Sunday. "There was no sense of shock here that something like that could happen in Britain because we've all been through it."
But even a partially favourable outcome will allow not just the families of those who perished but the entire city of Derry to move on. For so long as there is a logjam in the judicial process there will be a hold-up in the grieving process. The city has become defined by the events of Bloody Sunday. Coming into the Bogside you are struck by a huge white edifice announcing "You are now entering Free Derry". On the walls of the flats, which have now been renovated, are huge murals depicting what happened on the day. One row of flats, in Glenfada Park, has not been touched up. It bears a mural of an RUC man and a soldier beating a protester and bullet holes from Bloody Sunday which may be useful for the inquiry. The event is even being commodified. The Bogside has become one of the city's major tourist attractions; within Derry's historic walls you can buy T-shirts marking the event.
Given the current state of the peace process, the political ramifications of an inquiry which finds the authorities guilty of systematic and pervasive wrongdoing could be immense. If nothing else it will provide a tangible context for the "lack of trust" which republicans refer to as the obstacle in the path of decommissioning and remove the facade that the British government is nothing more than an honest broker in a local religious dispute.
"Trust is a two-way street," says Macbride. "Trust has not been forthcoming from them so there's not going to be much trust going to them."
But a critical report from Lord Saville will not only provide a boost for the people of Derry but a jolt for the British, who practise a selective amnesia when it comes to ugly parts of our recent history. It could force us, not by guilt but by intellect, to redefine who we are through what we, as a nation, have done. "I inherit from the past of my family, my city, my tribe, my nation a variety of debts, inheritances, rightful expectations and obligations," writes Alasdair MacIntyre in his book, After Virtue: A Study in Moral Theory. "I am born with a past; and to try to cut myself off from that past is to deform my present relationships. The possession of an historical identity and the possession of a social identity coincide."
Which brings us back to the two monuments. For through the different ways in which the American and British establishments recognise their specific Bloody Sundays one begins to see where greater trust could emerge. The plaque in Selma shows that when it comes to the past the US has an ability to sacrifice parts in favour of the whole. They will admit a specific wrongdoing so that you may still retain some faith in the country's broader ideological narrative. Such an approach suggests that the nation's political culture is underpinned by a notion of right and wrong. By admitting it has been wrong it has the ability to claim that it has also been right. This does not make American history more morally acceptable. But it does make the official versions of it more believable.
The absence of any common marker in Derry indicates how, in the United Kingdom, there is no such distinction. For when a nation rarely admits it has done wrong, even in the face of undeniable evidence, it denies the opportunity for any critical support. You can either believe in the whole or you can reject the whole. You cannot take it in parts. You cannot think that what happened in Derry was wrong and still believe in the union flag since the establishment still insists those wrongs were committed in the name of the union flag. Nowhere are these contradictions clearer than in Ireland. By apologising for the potato famine and expressing regret for Bloody Sunday, Tony Blair has made some commendable headway here. By setting up an inquiry he has set the ball rolling. Once again it will be down to a lord to pick it up and run with it.