Why does the US have to give $15 million to Poland for their Auschwitz memorial?

Hillary Clinton pledged that much from US funds to repair the old concentration camp. Last I heard we have a lot of unemployment, high taxes and a bad economy. Why don't private donors pay for it? Or Hilary herself? Does the Secretary of State have that much power to go on a spending spree when visiting heads of state, should they ask for money she'll commit to it like it's HER money? What else has she given the green light to?