What was being built during James Monroe's presidency that many considered the newest wonder of the world?

A canal that connected the Hudson River to Lake Erie.

Explanation:

The construction of this channel was something innovative and that generated very positive reactions to the public. First, this was a bold construction that used many innovative concepts, being considered one of the newest wonders in the world. Secondly, this construction would improve the lives of many people, as it would allow a fixed and continuous connection from the northwest to New York, facilitating transportation in a great way.

answer; creep;