  We present six spectroscopically confirmed massive protostructures, spanning
a redshift range of $2.5<z<4.5$ in the Extended Chandra Deep Field South
(ECDFS) field discovered as part of the Charting Cluster Construction in VUDS
and ORELSE (C3VO) survey. We identify and characterize these remarkable systems
by applying an overdensity measurement technique on an extensive data
compilation of public and proprietary spectroscopic and photometric
observations in this highly studied extragalactic field. Each of these six
protostructures, i.e., a large scale overdensity (volume $>9000$\thinspace
cMpc$^3$) of more than $2.5\sigma_{\delta}$ above the field density levels at
these redshifts, have a total mass $M_{tot}\ge10^{14.8}M_\odot$ and one or more
highly overdense (overdensity$\thinspace>5\sigma_{\delta}$) peaks. One of the
most complex protostructures discovered is a massive
($M_{tot}=10^{15.1}M_\odot$) system at $z\sim3.47$ that contains six peaks and
55 spectroscopic members. We also discover protostructures at $z\sim3.30$ and
$z\sim3.70$ that appear to at least partially overlap on sky with the
protostructure at $z\sim3.47$, suggesting a possible connection. We
additionally report on the discovery of three massive protostructures at
$z=2.67$, 2.80, and 4.14 and discuss their properties. Finally, we discuss the
relationship between star formation rate and environment in the richest of
these protostructures, finding an enhancement of star formation activity in the
densest regions. The diversity of the protostructures reported here provide an
opportunity to study the complex effects of dense environments on galaxy
evolution over a large redshift range in the early universe.
