Finding the "most recent" rows

I have a table (representing a set of observations) with datetime fields and a
non-unique place field.

e.g.
create table obs (
the_time datetime,
the_place char(8),
...other fields...
)

I'd like an efficient way to pull out the most recent row (i.e. highest
datatime) belonging to *each* of a number of places selected by a simple
query.

e.g. given a table such as:

the_time    the_place    ...
0910        London
1130        London
0910        Paris
0930        London
0840        Paris
1020        London
0740        Paris

I'd like to select:
1130        London
0910        Paris

Most of my attempts at this (as an SQL novice) feel very clumsy and
inefficient. Is there an efficient way of doing this in SQL?
-- 

Julian Scarfe