I'm interested in any historical examples people have of altruistic actions taken primarily to benefit future generations, which don't have strong positive effects for current generations. (So e.g. most climate change mitigation efforts wouldn't count, if we expect climate change to have a big negative impact on people currently alive - but maybe some do?)
Every culture has always been concerned about the future, the afterlife and so on, but it seems to me that worries about "remote" future generations are relatively recent. There are probably isolated counterexamples, though, which I believe are the ones you are looking for. Aside from that, in the animal reign, there is of course the instinctive concern about the "next" generation, which is in turn reproduced in every following generation.