M·AGRIPPA·L·F·COS·TERTIVM·FECIT - Pantheon

Pantheon - dedicated to the gods.

The inscription means:
M(ARCUS) AGRIPPA L(UCII) F(ILIUS) CO(N)S(UL) TERTIUM FECIT
"Marcus Agrippa, son of Lucius, built during his third consulate"

forum romanum.