  We discuss diphoton semi(exclusive) production in ultraperipheral $PbPb$
collisions at energy of $\sqrt{s_{NN}}=$ 5.5 TeV (LHC). The nuclear
calculations are based on equivalent photon approximation in the impact
parameter space. The cross sections for elementary $\gamma \gamma \to \gamma
\gamma$ subprocess are calculated including three different mechanisms: box
diagrams with leptons and quarks in the loops, a VDM-Regge contribution with
virtual intermediate hadronic excitations of the photons and the two-gluon
exchange contribution (formally three-loops). We got relatively high cross
sections in $PbPb$ collisions. This opens a possibility to study the $\gamma
\gamma \to \gamma \gamma$ (quasi)elastic scattering at the LHC. We find that
the cross section for elastic $\gamma\gamma$ scattering could be measured in
the lead-lead collisions for the diphoton invariant mass up to
$W_{\gamma\gamma} \approx 15-20$ GeV. We identify region(s) of phase space
where the two-gluon exchange contribution becomes important ingredient compared
to box and nonperturbative VDM-Regge mechanisms. We discuss also first results
concerning production of two $e^+ e^-$ pairs in UPCs of heavy ions. We
considered only double scattering mechanism.
