If you said Candlestick Park in San Francisco then you were correct.
This was the original configuration of Candlestick. You can see the wraparound grandstands in left field and the three-pole light towers.
Candlestick was enclosed and enlarged during the 1971 season. There are several '72 Topps cards that give you a look at the in-season construction.
It seems odd for so much work to be taking place during the baseball season. Usually you'd see work like that during the off-season. But I guess they wanted the extra seats ready for the '49er when they moved to Candlestick for the 1971 season. That left the Giants a construction zone stadium for the '71 season.