  M87 provides the best opportunity to study the base of a jet where it is
collimated and accelerated. The size of that region scales with the mass of the
black hole, and M87 has the best combination of high mass, proximity to the
Earth, and presence of a bright jet. VLBI observations of M87 can probe regions
under 100 gravitational radii where theoretical studies suggest that the jet
formation and acceleration occurs. A one-year sequence of 43 GHz observations
every 3 weeks on the VLBA is being used to study the structure and dynamics in
this region. Initial results from that effort are reported here, including the
observation of rapid motions - sufficiently rapid that more frequent
observations are planned for early 2008. The contribution ends with a
discussion of prospects for future VLBI observations of M87 with VSOP2. For
VSOP2, a strong recommendation is made that a series of daily observations at
43 GHz be planned.
