  The detection of thousands of extrasolar planets by the transit method
naturally raises the question of whether potential extrasolar observers could
detect the transits of the Solar System planets. We present a comprehensive
analysis of the regions in the sky from where transit events of the Solar
System planets can be detected. We specify how many different Solar System
planets can be observed from any given point in the sky, and find the maximum
number to be three. We report the probabilities of a randomly positioned
external observer to be able to observe single and multiple Solar System planet
transits; specifically, we find a probability of 2.518% to be able to observe
at least one transiting planet, 0.229% for at least two transiting planets, and
0.027% for three transiting planets. We identify 68 known exoplanets that have
a favourable geometric perspective to allow transit detections in the Solar
System and we show how the ongoing K2 mission will extend this list. We use
occurrence rates of exoplanets to estimate that there are $3.2\pm1.2$ and
$6.6^{+1.3}_{-0.8}$ temperate Earth-sized planets orbiting GK and M dwarf stars
brighter than $V=13$ and $V=16$ respectively, that are located in the Earth's
transit zone.
