Excavation began of the stadium of _Puteoli_, built by _Antoninus Pius_ in the gardens of Ciceronian Puteolanum. Firstly, part of the ambulatory on which the northern sector of the _cavea_ was built was freed of various dumps of material. The ambulatory structure was in _opus mixtum_ covered by a system of cross vaults, barrel vaults and ribbed vaults. The south wall was built with a double masonry curtain in which openings provided access to the _cavea_ ( _vomitoria_ ), whilst the north wall was formed by a series of arches on composite pilasters. The ambulatory was entered from the north, passing through a portico of which a number of cruciform pillars have been uncovered, with semi-columns almost completely in the round on the north side. Of this part of the portico the upper part of the external façade was preserved in view. Built in _opus latericium_ it was faced, probably for its entire height, with a pale coloured plaster. The northern arches of the ambulatory opened in this wall, framed by pilasters on top of which the piperno brackets that supported the poles for the _velarium_ were fixed. The _cavea_, with the usual tripartition, was built on an _opus vittatum_ extrados, on which the tiers for spectators and the steps leading from one sector to another rested. These elements were all constructed in large blocks of piperno of parallelepiped form. The _balteus_, still under excavation, was constituted by an _opus mixtum_ wall on an east-west alignment. The track, not yet discovered, was probably accessed from the east, passing through a monumental opening with several archways, with a shift in axis towards the south-east, of which only the northernmost, built of piperno blocks, has been identified to date.