In today’s daf, Menachot 28b, the Gemara discusses at length what the Menorah in the Beit HaMikdash looked like. There are excellent diagrams of this from the book Tavnit HaMishkan viKeilav (one diagram can be seen here on the left). These diagrams are available for downloading on our Resources page.
One thing that the Gemara does not discuss, however, is the general overall shape. Specifically, were the arms curved or bent? Did the arms emerging from the central column look like a inverted-arch, as we imagine it, or were they a V-shape? Because the Gemara does not discuss a special shape of the arms, a number of Rishonim are of the opinion that the arms were straight, and that the pairs emerging from the Menorah formed V-shapes. So, for example, we find the following picture, drawn by Rambam, in his Commentary to the Mishna on today’s Mishna:
However, with recent (and not-so-recent) archeological findings we now know that this is incorrect. Many engravings from the time of the Temple depict the Menorah as having arched arms. These include: the Arch of Titus, which stands in Rome and was erected as a monument to Titus’ destruction of the Temple; mosaics on synagogue floors from the time of the Second Temple; coins from the time of the Second Temple; and an engraving of the Menorah found in the Burnt House, a house of Kohanim that was destroyed during the time of the Destruction of the Temple, and that stood in direct proximity to the Beit HaMikdash. Below are pictures of all of the above: