today marks a month vs today mark a month

Some examples from the web:

• Today marks three months since Batman's defeat of the Mutant leader at the West River drainage site.
• Today marks exactly six months - and for the first time in history, not a single child has been paralyzed in Uttar Pradesh or Bihar.
• Today marks a critical time in the transatlantic relations which, six months after the direct terrorist attacks on the US, are straining under intense pressure.
• Today marks a critical juncture in our endeavor.
• PRESIDENT: Today marks a momentous day in human history.
• Madam President, Commissioner, ladies and gentlemen, our debate today marks a fork in the road between two crucial principles.
• Mr President, ladies and gentlemen, today marks a very important step in relations between Turkey and the European Union, particularly in terms of putting the Helsinki conclusions into practice.
• The document we have before us today marks a step towards reducing the incidence of illegal employment, which has so many adverse repercussions from a fiscal and social perspective.
• The existence of a Committee on Women's Rights and Gender Equality in the European Parliament and the report before the House today mark a high point in that process of evolution.
• The text put to the vote today marks a certain change in the way our institution views the concept of free trade.
• The regulation voted on today marks a highly significant success as it is the first time that the rights of passengers travelling by bus and coach will be protected by law.
• Madam President, Commissioner, ladies and gentlemen, the draft directive put before us today marks a great leap forwards in the realisation of our European Community, for it will be through EU citizens enjoying freedom of movement that we will achieve our objective.
• Triebig's easy installment plan lets you acquire this very model for just two marks a month.
• My father's pension is 70 marks a month, if he even gets it.
• You were paid 5,000 marks a month, as the contract required.
• You think you're superior, but you're quite an ordinary man... even if you did marry money... and people like me have got to slave for you... for 320 marks a month.
• Today marks the beginning of a new relationship between our two countries.
• Today marks the 80th Anniversary of the Social Security Act.
• Today marks the anniversary of the day they first encountered Moloch.
• And finally, today marks one year since we lost Andy Darden.

Some examples from the web:

• Today marks three months since Batman's defeat of the Mutant leader at the West River drainage site.
• Today marks exactly six months - and for the first time in history, not a single child has been paralyzed in Uttar Pradesh or Bihar.
• Today marks a critical time in the transatlantic relations which, six months after the direct terrorist attacks on the US, are straining under intense pressure.
• Today marks a critical juncture in our endeavor.
• PRESIDENT: Today marks a momentous day in human history.
• Madam President, Commissioner, ladies and gentlemen, our debate today marks a fork in the road between two crucial principles.
• Mr President, ladies and gentlemen, today marks a very important step in relations between Turkey and the European Union, particularly in terms of putting the Helsinki conclusions into practice.
• The document we have before us today marks a step towards reducing the incidence of illegal employment, which has so many adverse repercussions from a fiscal and social perspective.
• The existence of a Committee on Women's Rights and Gender Equality in the European Parliament and the report before the House today mark a high point in that process of evolution.
• The text put to the vote today marks a certain change in the way our institution views the concept of free trade.
• The regulation voted on today marks a highly significant success as it is the first time that the rights of passengers travelling by bus and coach will be protected by law.
• Madam President, Commissioner, ladies and gentlemen, the draft directive put before us today marks a great leap forwards in the realisation of our European Community, for it will be through EU citizens enjoying freedom of movement that we will achieve our objective.
• Triebig's easy installment plan lets you acquire this very model for just two marks a month.
• My father's pension is 70 marks a month, if he even gets it.
• You were paid 5,000 marks a month, as the contract required.
• You think you're superior, but you're quite an ordinary man... even if you did marry money... and people like me have got to slave for you... for 320 marks a month.
• Today marks the beginning of a new relationship between our two countries.
• Today marks the 80th Anniversary of the Social Security Act.
• Today marks the anniversary of the day they first encountered Moloch.
• And finally, today marks one year since we lost Andy Darden.