Isaac means “he laughs.” When Abraham and Sarah heard that they were going to have a son in their old age, they both laughed (17:17; 18:12). When Isaac was born, however, they and all their friends laughed with joy (21:6)!
Altars were tables or platforms used for presenting sacrifices to God. They could be built of stone, mud-brick, or dirt mounds. The first altar mentioned in the Bible is the one Noah built after the flood (8:20; see also 12:8).
What did the Tower of Babel look like? The Tower of Babel (11:1–9) probably resembled the ziggurats of ancient Mesopotamia. The most famous of these is the Great Ziggurat of Ur. Its remains can be seen today in southeastern Iraq.