Modular flooring tiles and system

Modular floor tiles include a first surface configured to receive weight. The first surface is supported by primary walls interior to and extending the full height of the tiles, and which may be intersecting to form a grid. Secondary walls of a lesser height support the primary walls, may be non-linear such as circular, and may support either side of vertices of intersecting primary walls. Joining members and corresponding receivers in the sides of tiles are dimensioned to engage one another from adjacent tiles to join the tiles and restrict lateral movement. Fastener(s) in each tile are associated with slots and may be selectively moved between unlocked and locked positions to restrict vertical movement. Some embodiments include cable channels with corresponding cover plates, and inclined portions providing ramps. Any number and combination of tiles may be connected to one another to form a modular flooring system.