<Tr> <Td> Best Guest Starring Role on Television </Td> <Td> Laura Benanti </Td> <Td> Nominated </Td> </Tr> <Tr> <Td> Best Superhero Adaptation Television Series </Td> <Td> Supergirl </Td> <Td> Nominated </Td> </Tr> <Tr> <Td> Best Supporting Actress on Television </Td> <Td> Calista Flockhart </Td> <Td> Nominated </Td> </Tr> <Tr> <Td> Breakthrough Performance </Td> <Td> Melissa Benoist </Td> <Td> Won </Td> </Tr>

Where was supergirl season 3 episode 21 filmed