  I present a set of long-term, direct, relativistic many-body computations of
model dense stellar clusters with up-to-date stellar-evolutionary, supernova
(SN), and remnant natal-kick models, including pair instability and pulsation
pair instability supernova (PSN and PPSN), using an updated version of NBODY7
N-body simulation program. The N-body model also includes stellar
evolution-based natal spins of BHs and treatments of binary black hole (BBH)
mergers based on numerical relativity. These, for the first time in a direct
N-body simulation, allow for second-generation BBH mergers. The set of 65
evolutionary models have initial masses $10^4M_\odot-10^5M_\odot$, sizes 1 pc-3
pc, metallicity $0.0001-0.02$, with the massive stars in primordial binaries
and they represent young massive clusters (YMC) and moderately massive open
clusters (OC). Such models produce dynamically-paired BBH mergers that agree
well with the observed masses, mass ratios, effective spin parameters, and
final spins of the LVC O1/O2 merger events, provided BHs are born with low or
no spin but spin up after undergoing a BBH merger or matter accretion onto it.
In particular, the distinctly higher mass, effective spin parameter, and final
spin of GW170729 merger event is naturally reproduced, as also the mass
asymmetry of the O3 event GW190412. The computed models produce massive,
$\sim100M_\odot$ BBH mergers with primary mass within the 'PSN gap' and also
yield mergers involving remnants in the 'mass gap'. They also suggest that YMCs
and OCs produce persistent, Local-Universe GW sources detectable by LISA. Such
clusters are also capable of producing eccentric LIGO-Virgo mergers.
