From Plaça del Rei it's worth a detour to see the two best surviving stretches of Barcelona's Roman walls, which once boasted 78 towers (as much a matter of prestige as of defence). One section is on the southern side of Plaça de Ramon Berenguer el Gran, with the 14th-century Capella Reial de Santa Àgata atop. Another piece of wall sits towards the northern end of Carrer del Sots-Tinent Navarro, while more can be seen at the Porta de Mar archaeological site.
The Romans built and reinforced these walls in the 3rd and 4th centuries CE, after the first attacks by Germanic tribes from the north.
