In Bereshis 1:28 God tells Adam to to conquer the land, וְכִבְשֻׁהָ. How or in what way was Adam supposed to do this? Build buildings? Farm? Something else?
In Lonely Man of Faith, throughout the first chapter, R' Soloveitchik develops the idea that man is charged with overcoming his environment and conquering nature. He achieves dignity by becoming the master of his own destiny. Thus, building hospitals and saving lives are fulfilments of this mandate (p. 16). On page 19, R' Soloveitchik writes that this is the embodiment of the charge to "fill the earth and subdue it." Quite to the contrary of R' Menachem Kasher, R' Soloveitchik writes that venturing into outer space is a fulfillment of this charge, not a violation of it.
Ramban ad loc writes that God's command to man to conquer the earth is a directive to man to rule over the animals, plants, and natural resources.
He gave them the power and rulership over the earth; to do whatever they wanted with the beasts and the swarming animals and all of those that slither on the ground; and to build and to uproot and plant and to quarry copper from its hills and [to do things] similar to this. And this is [all] included in its stating (above, verse 26), "and over all the earth." Source