The first church at the site was built before 1339 and stood until 1820.

The first church on the site was built before 1786.

It is thought to have been built before the end of the 15th century.

Of the single family homes 23 were built before 1919.

The original house on the site is thought to have been built before 1579.

A fourth line is not expected to be built before 2020.

So the ship could not have been built before 1445.

The house - which was built in 1870, a year before the Chicago fire - has been through some hard times.

Plants built before 1970 do not have to meet the current standards.

In general, just buildings built before 1940 will be included.