lets say i have 2 columns in sheet1: column A lists names of cities, column B
the countries they are in. in sheet2, i would like to do a data validation in
column A based on list of cities in sheet1. in addition, i would like column
B in sheet2 to automatically pick the country from the list in sheet1 in
which the selected city in column A is.

the number of rows in sheet2 could be endless and therefore copying a lookup
function from row to row is not desired.

In an older version of excel, I seem to remember a procedure using "cell
span" ?