>>> summer for the earthquake, you remember where you were and did you not want to be inside the washington monument. the shake diagnose a lot of damage. just today we learned it will likely be closed until next year. the repairs could not have been paid for if it wasn't for the generosity of one wealthy american. call this a gift to the public from a member of the top 1% of the 1%. the story from nbc's tom costello.
>> reporter: the new video of the damage assessment on the washington monument is truly breath taking.
>> this is the large crack on the west elevation.
>> reporter: cracks and chipped corners running across the monument, both outside and inside, where they used ground-penetrating radar to follow the fracture lines. repairing it will mean closing the obolisk for a year and cost a fortune $15 million. congress agreed to pay for half, but today a history buff and son of a postal worker said he will pay the rest.
>> i am very pleased as a citizen of this country i have had the good fortune to be able to help in this way.
>> reporter: since his first visit as an 8-year-old boy, david ruben stein loved the nation's monument to its first president. he co-founded the carlyle group where he became one of the country's richest men. when the wake hit last august he called the parks service.
>> i would suggest perhaps it hadn't even stopped shaking before david rubenstein came to me and asked if he could help.
>> reporter: his philanthropy is well known. he spent tens of millions of dollars buying the magna carta and decoration of independence for the government to display and donated $4.5 million to the national zoo's panda program. visitors to the monument today were thankful.
>> it stands for so much more than just the monument. he's spreading it across the country in a very, very relevant time.
>> reporter: more than 100 years ago private donations of $1 each built the monument. it's only fitting, says rubenstein, that the tradition continues. tom costello, nbc news, washington.
